index.html.in

   1 <!doctype html>
   2 <html lang="en-US">
   3   <head>
   4     <meta charset="utf-8">
   5     <meta name="viewport" content="width=device-width, initial-scale=1" />
   6     <link rel="icon"
   7           type="image/svg+xml"
   8           href="data:image/svg+xml;base64,@FAVICON@" />
   9
  10     <title>
  11       CharmBypass: got that transit equity
  12     </title>
  13
  14     <style>
  15       body {
  16         /* For consistency with the SVG */
  17         font-family: sans-serif;
  18       }
  19
  20       fieldset {
  21         margin-top: 1em;
  22         padding-top: 1em;
  23       }
  24
  25       input[type=submit] {
  26         margin-top: 1em;
  27         margin-bottom: 1em;
  28       }
  29
  30       legend {
  31         font-weight: bold;
  32       }
  33
  34       /* Display form errors for the one browser that doesn't support
  35        * them natively, mobile Firefox. We use "visibility" to toggle
  36        * it on and off, but "display" to hide it completely in non-
  37        * stupid web browsers. */
  38       #marc-form-errors {
  39         color: #a00;
  40         visibility: hidden;
  41         display: none;
  42       }
  43
  44       svg {
  45         /* Set the height to 100% of the screen, which we'll keep; and the
  46          * initial position to (0,0), which we're going to change
  47          * every time the window is resized, because the exact amount
  48          * that we have to slide the SVG to the left to get the ticket
  49          * into the center will change. */
  50         position: fixed;
  51         top: 0;
  52         left: 0;
  53         height: 100%;
  54
  55         /* Hide everything by default. We only show it once the user has
  56          * submitted the menu form */
  57         display: none;
  58       }
  59
  60       /* The blinking fade in/out animation for the ticket date and time */
  61       @keyframes blink {
  62         25% { opacity: 0.5; }
  63         50% { opacity: 0;   }
  64         75% { opacity: 0.5; }
  65       }
  66
  67       #tickettime, #ticketdate {
  68         /* 300 two-second blinks is ten minutes */
  69         animation: blink 2s linear 300;
  70       }
  71
  72       /* Define, load, and specify the custom font we use for the ticket
  73        * date, time, and service name. */
  74       @font-face {
  75         font-family: "CharmBypass Regular";
  76         src:
  77           url("data:font/woff2;base64,@CBPREGULAR@") format("woff2")
  78       }
  79
  80       #origindest, #servicename, #tickettime, #ticketdate, #codetext, #zone {
  81         font-family: "CharmBypass Regular", sans-serif;
  82       }
  83
  84       @font-face {
  85         font-family: "CharmBypass Bold";
  86         src:
  87           url("data:font/woff2;base64,@CBPBOLD@") format("woff2")
  88       }
  89
  90       #serviceid {
  91         font-family: "CharmBypass Bold", sans-serif;
  92       }
  93
  94       /************************/
  95       /* Scrolling animations */
  96       /************************/
  97
  98       /* Bus */
  99       @keyframes busroll {
 100         from { transform: translateX(0%);    }
 101         to   { transform: translateX(-100%); }
 102       }
 103
 104       #bus {
 105         animation: busroll 15s linear infinite;
 106       }
 107
 108
 109       /* Tram */
 110       @keyframes tramroll {
 111         from { transform: translateX(0%);   }
 112         to   { transform: translateX(100%); }
 113       }
 114
 115       #tram {
 116         animation: tramroll 15s linear infinite;
 117       }
 118
 119
 120       /* Train */
 121       @keyframes trainroll {
 122         from { transform: translateX(0%);   }
 123         to   { transform: translateX(100%); }
 124       }
 125
 126       #train {
 127         animation: trainroll 10s linear infinite;
 128       }
 129
 130
 131       /* Clouds */
 132       @keyframes cloudsfloat {
 133         from { transform: translateX(0%);   }
 134         to   { transform: translateX(-50%); }
 135       }
 136
 137       #clouds {
 138         animation: cloudsfloat 25s linear infinite;
 139       }
 140
 141       @keyframes cloudscopyfloat {
 142         from { transform: translateX(0%);   }
 143         to   { transform: translateX(-50%); }
 144       }
 145
 146       #cloudscopy {
 147         animation: cloudscopyfloat 25s linear infinite;
 148       }
 149
 150
 151       /* Trees */
 152       @keyframes treespass {
 153         from { transform: translateX(0%);   }
 154         to   { transform: translateX(-50%); }
 155       }
 156
 157       #trees {
 158         /* The trees move a little faster than the clouds */
 159         animation: treespass 16s linear infinite;
 160       }
 161
 162       @keyframes treescopypass {
 163         from { transform: translateX(0%);   }
 164         to   { transform: translateX(-50%); }
 165       }
 166
 167       #treescopy {
 168         /* The trees move a little faster than the clouds */
 169         animation: treescopypass 16s linear infinite;
 170       }
 171
 172
 173       /* City skyline */
 174       @keyframes cityscroll {
 175         from { transform: translateX(0%);   }
 176         to   { transform: translateX(-50%); }
 177       }
 178
 179       #city {
 180         /* The city moves faster than the clouds but slower
 181          * than the trees */
 182         animation: cityscroll 20s linear infinite;
 183       }
 184
 185       @keyframes citycopyscroll {
 186         from { transform: translateX(0%);   }
 187         to   { transform: translateX(-50%); }
 188       }
 189
 190       #citycopy {
 191         /* The city moves faster than the clouds but slower
 192          * than the trees */
 193         animation: citycopyscroll 20s linear infinite;
 194       }
 195     </style>
 196   </head>
 197
 198   <body>
 199     <div id="menu">
 200       <h1>CharmBypass</h1>
 201       <p><strong>got that <em>transit equity</em></strong></p>
 202
 203       <ol>
 204         <li>
 205           <a href="https://michael.orlitzky.com/articles/charmbypass_pt._1%3A_introducing_charmbypass.xhtml">
 206             Introduction
 207           </a>
 208         </li>
 209       </ol>
 210
 211       <form>
 212         <fieldset>
 213           <legend>Local Bus, Light Rail, or Metro</legend>
 214           <div>
 215             <label for="code1">
 216               Daily security code (optional):
 217             </label>
 218             <input id="code1"
 219                    name="code"
 220                    type="text"
 221                    size="2"
 222                    minlength="2"
 223                    maxlength="2"
 224                    pattern="[a-zA-Z0-9]*" />
 225           </div>
 226           <input type="hidden" name="servicename" value="BaltimoreLink" />
 227           <input type="submit" name="go" value="Generate Ticket" />
 228         </fieldset>
 229       </form>
 230       <form>
 231         <fieldset>
 232           <legend>Commuter Bus</legend>
 233           <input type="hidden" name="serviceid" value="R" />
 234           <input type="hidden" name="servicename" value="Commuter Bus" />
 235
 236           <div>
 237             <label for="code2">
 238               Daily security code (optional):
 239             </label>
 240             <input id="code2"
 241                    name="code"
 242                    type="text"
 243                    size="2"
 244                    minlength="2"
 245                    maxlength="2"
 246                    pattern="[a-zA-Z0-9]*" />
 247           </div>
 248
 249           <p>
 250             Zone<sup>&dagger;</sup>:
 251           </p>
 252           <div>
 253             <input type="radio" required
 254                    name="zone"
 255                    id="zone1"
 256                    value="Zone 1" />
 257             <label for="zone1">Zone 1</label>
 258           </div>
 259           <div>
 260             <input type="radio" required
 261                    name="zone"
 262                    id="zone2"
 263                    value="Zone 2" />
 264             <label for="zone2">Zone 2</label>
 265           </div>
 266           <div>
 267             <input type="radio" required checked
 268                    name="zone"
 269                    id="zone3"
 270                    value="Zone 3" />
 271             <label for="zone3">Zone 3</label>
 272           </div>
 273           <div>
 274             <input type="radio" required
 275                    name="zone"
 276                    id="zone4"
 277                    value="Zone 4" />
 278             <label for="zone4">Zone 4</label>
 279           </div>
 280           <div>
 281             <input type="radio" required
 282                    name="zone"
 283                    id="zone5"
 284                    value="Zone 5" />
 285             <label for="zone5">Zone 5</label>
 286           </div>
 287
 288           <input type="submit" name="go" value="Generate Ticket" />
 289
 290           <p>
 291             <sup>&dagger;</sup>
 292             On the MTA's PDF schedule for your route
 293           </p>
 294         </fieldset>
 295       </form>
 296       <form>
 297         <fieldset>
 298           <legend>MARC Train</legend>
 299
 300           <div>
 301             <label for="code3">
 302               Daily security code (optional):
 303             </label>
 304             <input id="code3"
 305                    name="code"
 306                    type="text"
 307                    size="2"
 308                    minlength="2"
 309                    maxlength="2"
 310                    pattern="[a-zA-Z0-9]*" />
 311           </div>
 312
 313           <p>Origin:</p>
 314           <div>
 315             <input type="radio" required checked
 316                    name="origin"
 317                    id="origin1"
 318                    value="BAL" />
 319             <label for="origin1">Baltimore/Penn (Penn Line)</label>
 320           </div>
 321           <div>
 322             <input type="radio" required
 323                    name="origin"
 324                    id="origin2"
 325                    value="BCA" />
 326             <label for="origin2">Baltimore/Camden (Camden Line)</label>
 327           </div>
 328           <div>
 329             <input type="radio" required
 330                    name="origin"
 331                    id="origin3"
 332                    value="BWE" />
 333             <label for="origin3">Bowie State (Penn Line)</label>
 334           </div>
 335           <div>
 336             <input type="radio" required
 337                    name="origin"
 338                    id="origin4"
 339                    value="BWI" />
 340             <label for="origin4">BWI Airport (Penn Line)</label>
 341           </div>
 342           <div>
 343             <input type="radio" required
 344                    name="origin"
 345                    id="origin5"
 346                    value="CPK" />
 347             <label for="origin5">College Park (Camden Line)</label>
 348           </div>
 349           <div>
 350             <input type="radio" required
 351                    name="origin"
 352                    id="origin6"
 353                    value="SEB" />
 354             <label for="origin6">Seabrook (Penn Line)</label>
 355           </div>
 356           <div>
 357             <input type="radio" required
 358                    name="origin"
 359                    id="origin7"
 360                    value="WAS" />
 361             <label for="origin7">Washington D.C.</label>
 362           </div>
 363           <div>
 364             <input type="radio" required
 365                    name="origin"
 366                    id="origin8"
 367                    value="WBL" />
 368             <label for="origin8">West Baltimore (Penn Line)</label>
 369           </div>
 370
 371           <p>Destination:</p>
 372           <div>
 373             <input type="radio" required
 374                    name="destination"
 375                    id="destination1"
 376                    value="BAL" />
 377             <label for="destination1">Baltimore/Penn (Penn Line)</label>
 378           </div>
 379           <div>
 380             <input type="radio" required
 381                    name="destination"
 382                    id="destination2"
 383                    value="BCA" />
 384             <label for="destination2">Baltimore/Camden (Camden Line)</label>
 385           </div>
 386           <div>
 387             <input type="radio" required
 388                    name="destination"
 389                    id="destination3"
 390                    value="BWE" />
 391             <label for="destination3">Bowie State (Penn Line)</label>
 392           </div>
 393           <div>
 394             <input type="radio" required
 395                    name="destination"
 396                    id="destination4"
 397                    value="BWI" />
 398             <label for="destination4">BWI Airport (Penn Line)</label>
 399           </div>
 400           <div>
 401             <input type="radio" required
 402                    name="destination"
 403                    id="destination5"
 404                    value="CPK" />
 405             <label for="destination5">College Park (Camden Line)</label>
 406           </div>
 407           <div>
 408             <input type="radio" required
 409                    name="destination"
 410                    id="destination6"
 411                    value="SEB" />
 412             <label for="destination6">Seabrook (Penn Line)</label>
 413           </div>
 414           <div>
 415             <input type="radio" required checked
 416                    name="destination"
 417                    id="destination7"
 418                    value="WAS" />
 419             <label for="destination7">Washington D.C.</label>
 420           </div>
 421           <div>
 422             <input type="radio" required
 423                    name="destination"
 424                    id="destination8"
 425                    value="WBL" />
 426             <label for="destination8">West Baltimore (Penn Line)</label>
 427           </div>
 428
 429           <p id="marc-form-errors">OK</p>
 430
 431           <input type="hidden" name="serviceid" value="R" />
 432           <input type="hidden" name="servicename" value="MARC Train" />
 433           <input type="submit"
 434                  name="go"
 435                  id="marc-submit"
 436                  value="Generate Ticket" />
 437         </fieldset>
 438       </form>
 439     </div>
 440
 441     @SVGDATA@
 442
 443     <script>
 444
 445       /**
 446        * Center the ticket within the browser by translating the SVG
 447        * until the ticket and the viewport centerlines coincide.
 448        */
 449       function center_ticket() {
 450         /* We're relying on the SVG being the full height of the
 451          * viewport already, and on the aspect ratio being
 452          * preserved. First, find the center of the ticket. */
 453         const r = document.getElementById("ticket").getBoundingClientRect();
 454         const c = r.left + (r.width / 2);
 455
 456         /* That's the center-line of the ticket. We want to move it to
 457          * the center-line of the viewport. */
 458         const vc = document.documentElement.clientWidth / 2;
 459
 460         /* This is how much we need to translate the SVG */
 461         const hdelta = vc - c;
 462
 463         /* But before we can set the absolute left-coordinate of the
 464          * SVG, we need to know where it is now. Note: without the
 465          * "px" this doesn't default to pixels like CSS does. */
 466         const svg = document.querySelector("svg");
 467         svg.style.left = (svg.getBoundingClientRect().left + hdelta) + "px";
 468       }
 469
 470
 471       /**
 472        * Set the service identifier from the querystring if it's there.
 473        * Otherwise, leave it at the default of "F".
 474        */
 475       function set_service_id() {
 476         const sid = document.getElementById("serviceid");
 477
 478         /* Get the "serviceid" from the querystring if it's there */
 479         const params = new URLSearchParams(document.location.search);
 480         if (params.get("serviceid")) {
 481           sid.textContent = params.get("serviceid");
 482         }
 483       }
 484
 485
 486       /**
 487        * Set the service name from the querystring if it's there.
 488        * Otherwise, leave it at the default of "BaltimoreLink".
 489        */
 490       function set_service_name() {
 491         const sid = document.getElementById("servicename");
 492
 493         /* Get the "servicename" from the querystring if it's there */
 494         const params = new URLSearchParams(document.location.search);
 495         if (params.get("servicename")) {
 496           sid.textContent = params.get("servicename");
 497         }
 498       }
 499
 500
 501       /**
 502        * Set the zone from the given "zone" parameter and then unhide it.
 503        */
 504       function set_zone(zone) {
 505         const z = document.getElementById("zone");
 506
 507         z.textContent = zone;
 508         z.style.display = "block"; /* hidden by default */
 509       }
 510
 511
 512       /**
 513        * Resize the  ticket background based on the service name.
 514        * The BaltimoreLink, Commuter Bus, and MARC Train tickets
 515        * are all different heights and are arranged vertically a
 516        * bit different.
 517        *
 518        * Rather than design three completelty separate tickets and
 519        * then have to keep track of which one we're using, I have
 520        * instead decided to use one ticket and to reposition it
 521        * on-the-fly based on the service name. This is necessarily
 522        * a bit ugly because it involves a lot of magic numbers that
 523        * can only be explained if you open up inkscape with a CharmPass
 524        * screenshot to see where things belong and how to get them there.
 525        *
 526        * The SVG was designed with BaltimoreLink in mind, so this
 527        * is a no-op if the service is BaltimoreLink.
 528        */
 529       function resize_ticket() {
 530         /* Get the "servicename" from the querystring if it's there */
 531         const params = new URLSearchParams(document.location.search);
 532         const tbg = document.getElementById("ticketbg");
 533         const t = document.getElementById("ticket");
 534         const sn = document.getElementById("servicename");
 535
 536         if (params.get("servicename") === "Commuter Bus") {
 537           /* The top of the background is initially at y=246.859, and
 538            * we scale it by a factor of 1.12 to y=276.482 for a change
 539            * of 29.623. So after we scale it, we translate it upwards
 540            * by that amount to put it back where it started. */
 541           tbg.setAttribute("transform", "translate(0 -29.623) scale(1 1.12)");
 542
 543           /* Now translate the entire ticket up by the magic amount, 1/5
 544            * of the size change we made to the background. This ratio
 545            * was found by measuring pixels in side-by-side screenshots
 546            * of BaltimoreLink and Commuter Bus tickets. */
 547           t.setAttribute("transform", "translate(0 -9.33)");
 548
 549           /* More magic numbers discovered by comparing the two
 550            * tickets overlayed in inkscape */
 551           sn.setAttribute("transform", "translate(0 64.28)");
 552         }
 553         else if (params.get("servicename") === "MARC Train") {
 554           /* insane tricks are explained above */
 555           tbg.setAttribute("transform",
 556                            "translate(0 -72.378) scale(1 1.2932)");
 557           t.setAttribute("transform", "translate(0 -67.17)");
 558           sn.setAttribute("transform", "translate(0 131.0)");
 559         }
 560       }
 561
 562
 563       /**
 564        * Set the security code from the querystring if it was given;
 565        * otherwise generate a random code.
 566        */
 567       function set_code() {
 568         const ct = document.getElementById("codetext");
 569
 570         /* Get the "code" from the querystring if it's there */
 571         const params = new URLSearchParams(document.location.search);
 572         if (params.get("code")) {
 573           ct.textContent = params.get("code").toUpperCase();
 574         }
 575         else {
 576           /* Otherwise, use a random code */
 577           const bucket = ["0","1","2","3","4","5","6","7","8","9",
 578                           "A","B","C","D","E","F","G","H","I","J",
 579                           "K","L","M","N","O","P","Q","R","S","T",
 580                           "U","V","W","X","Y","Z"];
 581
 582           /* Two random ints between 0 and 35 */
 583           const i1 = Math.floor(Math.random() * 36);
 584           const i2 = Math.floor(Math.random() * 36);
 585           const d1 = bucket[i1];
 586           const d2 = bucket[i2];
 587           ct.textContent = d1 + d2;
 588         }
 589       }
 590
 591
 592       /**
 593        * Center the security code within its container.
 594        *
 595        * Some codes like "II" and "WW" can take up wildly different
 596        * amounts of horizonetal space, but they should always be
 597        * centered inside their little red box. This turns out to be
 598        * harder than it sounds because we can only find the width of
 599        * the code in browser coordinates, whereas its "x" coordinate
 600        * is in SVG coordinates. Anyway, we do it.
 601        */
 602       function center_code() {
 603         /* Center the security code inside its red box */
 604         const ct = document.getElementById("codetext");
 605         const bg = document.getElementById("codebg");
 606
 607         /* First, find the center of the red box */
 608         const r1 = bg.getBoundingClientRect();
 609         const c1 = r1.left + (r1.width / 2);
 610
 611         /* Now the center of the code text */
 612         const r2 = ct.getBoundingClientRect();
 613         const c2 = r2.left + (r2.width / 2);
 614
 615         /* What do we add to c2 to make it equal to c1? */
 616         const hdelta = c1 - c2;
 617
 618         /* We've measured everything so far in "client rect"
 619          * coordinates, because that's the only available measurement
 620          * we have for the width of the <text> element. But when we
 621          * reposition that <text> element, it will be by adjusting its
 622          * "x" attribute, and that attribute uses a different coordinate
 623          * system than the client rect does. Specifically, "x" refers to
 624          * an offset within the SVG's coordinate system, and the client
 625          * rect coordinates are pixels on-screen. To convert between the
 626          * two, we can take the "width" attribute of the background
 627          * element and compare it to the width of the background
 628          * element's client rect. Since the size of the background is
 629          * fixed, this should give us a multiplier that turns client rect
 630          * distances (what we have) into SVG distances (what we want) */
 631         const client_to_svg = parseFloat(bg.getAttribute("width"))/r1.width;
 632
 633         /* Convert hdelta from client rect to SVG coordinates */
 634         const svg_hdelta = hdelta * client_to_svg;
 635
 636         /* Since this <text> element has an "x" attribute it's easier for
 637          * us to shift that than it is to mess with the "left" style. */
 638         ct.setAttribute("x", parseFloat(ct.getAttribute("x")) + svg_hdelta);
 639       }
 640
 641       /**
 642        * Set the ticket's expiration date and time.
 643        *
 644        * BaltimoreLink and MARC Train tickets expire after 90 minutes;
 645        * while Commuter Bus tickets expire after 10 minutes.
 646        */
 647       function set_ticket_expiry() {
 648         /* There are two parameters, time and date, that we store in one
 649          * underlying "date" variable. */
 650         const date = new Date();
 651
 652         /* BaltimoreLink and MARC Train */
 653         let minutes = 90;
 654         const params = new URLSearchParams(document.location.search);
 655         if (params.get("servicename") === "Commuter Bus") {
 656           /* Commuter bus tickets are only valid for ten minutes */
 657           minutes = 10;
 658         }
 659
 660         /* We use the low-level get/setTime to change the number of
 661          * milliseconds since the epoch that this date represents
 662          * Obviously correct, and avoids all suspicious corner cases
 663          * for a few more decades. */
 664         date.setTime(date.getTime() + (minutes*60*1000));
 665
 666         tt = document.getElementById("tickettime");
 667         tt.textContent = date.toLocaleTimeString();
 668
 669         const td = document.getElementById("ticketdate");
 670         const dateopts = {
 671           day: "2-digit",
 672           month: "2-digit",
 673           year: "2-digit"
 674         };
 675         td.textContent = date.toLocaleDateString("en-US", dateopts);
 676       }
 677
 678
 679       /**
 680        * Swap the day/night sky colors.
 681        *
 682        * We use CSS classes to keep track of the current state because
 683        * it's a tiny bit cleaner than a global variable, but for some
 684        * reason we can't use those same classes to actually change the
 685        * color. (The classes, change, but the color doesn't.) Rather
 686        * than waste time trying to explain this, we just set the "fill"
 687        * attribute ourselves whenever we swap classes.
 688        */
 689       function swap_day_night() {
 690         const sky = document.getElementById("sky");
 691
 692         if (sky.getAttribute("class") === "night") {
 693           sky.setAttribute("fill", "#efb02f");
 694           sky.setAttribute("class", "day");
 695         }
 696         else {
 697           /* Put this case second so that the first time the
 698            * screen is tapped (when there are no classes on
 699            * the sky element) the color still changes. */
 700           sky.setAttribute("fill", "#143b66");
 701           sky.setAttribute("class", "night");
 702         }
 703       }
 704
 705
 706       /**
 707        * Compute the zone (string) for the given origin/destination pair.
 708        *
 709        * If we don't know it or if you chose in invalid pair (destination
 710        * not on the same line as your origin?) then null is returned.
 711        */
 712       function compute_marc_zone(src, dest) {
 713
 714         /* Sorted on the first component, then the second.
 715          *
 716          * Key:
 717          *
 718          *   $6.00 => 1
 719          *   $7.00 => 2
 720          *   $8.00 => 3
 721          *   $9.00 => 4
 722          */
 723         const zone_map = {
 724           BAL_BWE: 2,
 725           BAL_BWI: 1,
 726           BAL_SEB: 3,
 727           BAL_WAS: 4,
 728           BAL_WBL: 1,
 729           BCA_CPK: 3,
 730           BCA_WAS: 4,
 731           BWE_BWI: 1,
 732           BWE_SEB: 1,
 733           BWE_WAS: 2,
 734           BWE_WBL: 2,
 735           BWI_SEB: 2,
 736           BWI_WAS: 3,
 737           BWI_WBL: 1,
 738           SEB_WAS: 1,
 739           SEB_WBL: 3,
 740           WAS_WBL: 4
 741         };
 742
 743         /* Forward direction key for zone_map */
 744         const fwd = src + "_" +  dest;
 745
 746         /* Reverse direction key for zone_map. The zone_map only
 747          * has them listed in one direction, so we check both
 748          * directions here. */
 749         const rev = dest + "_" +  src;
 750
 751         /* The default. Obviously wrong for when we don't
 752          * have the necessary data. */
 753         let zone = -1;
 754
 755         if (zone_map[fwd]) {
 756           zone = zone_map[fwd];
 757         }
 758         else if (zone_map[rev]) {
 759           zone = zone_map[rev];
 760         }
 761
 762         /* Convert the number to a string */
 763         switch (zone) {
 764           case 1:
 765             return "One Zone";
 766           case 2:
 767             return "Two Zone";
 768           case 3:
 769             return "Three Zone";
 770           case 4:
 771             return "Four Zone";
 772           default:
 773             return null;
 774         }
 775       }
 776
 777
 778       /**
 779        * Compute and set the zone.
 780        *
 781        * We can be given a zone in two ways. First, on Commuter Bus
 782        * tickets, it is given explicitly via the querystring. But
 783        * It can also be specified implicitly via the origin and
 784        * destination on a MARC Train ticket. Here we try both and
 785        * then call set_zone() with the result if something worked.
 786        */
 787       function compute_and_set_zone() {
 788         const params = new URLSearchParams(document.location.search);
 789         const src = params.get("origin");
 790         const dest = params.get("destination");
 791
 792         if (src && dest) {
 793           /* MARC Train. We can assume that compute_marc_zone() doesn't
 794            * return null because that's part of our form validation. */
 795           const zone = compute_marc_zone(src, dest);
 796           set_zone(zone);
 797         }
 798         else if (params.get("zone")) {
 799           /* Commuter Bus */
 800           set_zone(params.get("zone"));
 801         }
 802       }
 803
 804
 805       /**
 806        * Set the origin and destination for the MARC Train if they
 807        * were provided, and unhide them if so.
 808        */
 809       function set_marc_origin_destination() {
 810         const params = new URLSearchParams(document.location.search);
 811         if (!params.get("origin") || !params.get("destination")) {
 812           return;
 813         }
 814
 815         const src = params.get("origin");
 816         const dest = params.get("destination");
 817
 818         /* origindest contains both the origin and destination */
 819         const origindest = document.getElementById("origindest");
 820
 821         const origin = document.getElementById("origin");
 822         const destination = document.getElementById("destination");
 823
 824         origin.textContent = params.get("origin");
 825         destination.textContent = params.get("destination");
 826
 827         origindest.style.display = "block"; /* hidden by default */
 828       }
 829
 830
 831       /**
 832        * Hide the menu and display the ticket. This is what happens
 833        * when you submit the form.
 834        */
 835       function go() {
 836         /* To create our "window" onto the scene, we're going to slide the
 837          * SVG off the left-hand side of the screen, and we don't want
 838          * scroll bars to appear. */
 839         document.body.style.overflow = "hidden";
 840         document.body.style.margin = "0";
 841         document.body.style.padding = "0";
 842
 843         const svg = document.querySelector("svg");
 844         const menu = document.getElementById("menu");
 845         svg.style.display = "initial";
 846         menu.style.display = "none";
 847       }
 848
 849       /**
 850        * Determine if the user agent is mobile Firefox.
 851        */
 852       function ua_is_mobile_ff() {
 853         const ua = navigator.userAgent.toLowerCase();
 854         return (ua.includes("firefox") && ua.includes("mobile"));
 855       }
 856
 857       /**
 858        * Validate the MARC form's origin/destination.
 859        *
 860        * We don't want the user to be able to choose a pair of stops that
 861        * aren't actually connected by the same MARC line. If we don't have
 862        * zone information for the (origin,destination) pair, that indicates
 863        * that it's probably not a valid choice; otherwise I would have
 864        * filled in the information from the CharmPass app already.
 865        *
 866        * All browsers except mobile Firefox let us call setCustomValidity()
 867        * to provide an error message that is displayed if the user tries
 868        * to submit invalid choices. But amazingly, mobile Firefox does not:
 869        *
 870        *   https://bugzilla.mozilla.org/show_bug.cgi?id=1510450
 871        *
 872        * Instead we have to work around it (in that one browser) by
 873        * showing/hiding a paragraph that we fill with the errors.
 874        */
 875       function validate_origin_destination(event) {
 876         const origins = document.getElementsByName("origin");
 877         const destinations = document.getElementsByName("destination");
 878         const mfe = document.getElementById("marc-form-errors");
 879         const marcsubmit = document.getElementById("marc-submit");
 880
 881         if (ua_is_mobile_ff()) {
 882           /* Even though this is only for one browser, empty paragraphs
 883            * are handled inconsistently and should be avoided as a rule.
 884            * So, we make it say "OK" before we hide it. */
 885           mfe.textContent = "OK";
 886           mfe.style.visibility = "hidden";
 887           marcsubmit.disabled = false;
 888         }
 889
 890         let src = null;
 891         let dest = null;
 892         origins.forEach((x) => { if (x.checked) src = x; })
 893         destinations.forEach((x) => {
 894           if (x.checked) dest = x;
 895
 896           /* clear all errors before possibly setting one */
 897           x.setCustomValidity('');
 898         })
 899
 900         if (src.value === dest.value) {
 901           let err = "Origin and destination are the same";
 902           dest.setCustomValidity(err);
 903
 904           if (ua_is_mobile_ff()) {
 905             mfe.textContent = err;
 906             mfe.style.visibility = "visible";
 907             marcsubmit.disabled = true;
 908           }
 909         }
 910         else if (compute_marc_zone(src.value, dest.value) === null) {
 911           let err = "Origin and destination are on different lines";
 912           dest.setCustomValidity(err);
 913
 914           if (ua_is_mobile_ff()) {
 915             mfe.textContent = err;
 916             mfe.style.visibility = "visible";
 917             marcsubmit.disabled = true;
 918           }
 919         }
 920       }
 921
 922       /*****************************************************/
 923       /* Add event handlers for all of the functions above */
 924       /*****************************************************/
 925
 926       const params = new URLSearchParams(document.location.search);
 927       if (params.get("go")) {
 928         /* First unhide the SVG (swap it with the form) */
 929         window.addEventListener("load", go);
 930
 931         /* Center the ticket once when the page has loaded */
 932         window.addEventListener("load", center_ticket);
 933
 934         /* Re-center the ticket when the window is resized */
 935         window.addEventListener("resize", center_ticket);
 936
 937         /* Set the service identifier when the page has loaded */
 938         window.addEventListener("load", set_service_id);
 939
 940         /* Set the service name when the page has loaded */
 941         window.addEventListener("load", set_service_name);
 942
 943         /* Resize the ticket background if necessary */
 944         window.addEventListener("load", resize_ticket);
 945
 946         /* Set the security code text when the page has loaded */
 947         window.addEventListener("load", set_code);
 948
 949         /* Center the security code text when the page has loaded; in
 950          * particular, after we set the code. */
 951         window.addEventListener("load", center_code);
 952
 953         /* Set the ticket expiration date/time upon page load */
 954         window.addEventListener("load", set_ticket_expiry);
 955
 956         /* Set the MARC Train origin and destination, if applicable */
 957         window.addEventListener("load", set_marc_origin_destination);
 958
 959         /* Compute and set the zone, if applicable */
 960         window.addEventListener("load", compute_and_set_zone);
 961
 962         /* Swap colors when the screen is tapped */
 963         document.body.addEventListener("click", swap_day_night);
 964       }
 965       else {
 966         /* If we haven't submitted the form yet, set up change handlers
 967          * for the origin/destination radio buttons that validate that
 968          * the origin and destination are on the same line. */
 969         document.getElementsByName("origin").forEach(
 970          (x) => x.addEventListener("change", validate_origin_destination)
 971         );
 972         document.getElementsByName("destination").forEach(
 973          (x) => x.addEventListener("change", validate_origin_destination)
 974         );
 975
 976         /* Also do it when the page loads, because firefox likes to
 977          * remember your selection even after the page reloads. */
 978         window.addEventListener("load", validate_origin_destination);
 979
 980         /* Finally, we have to babysit mobile Firefox, who doesn't
 981          * support HTML5 form validation going into 2024. Turn on
 982          * the little form errors paragraph so we can toggle its
 983          * visibility (and make it display the error) when the user
 984          * makes an invalid selection. */
 985         window.addEventListener("load", () => {
 986           if (ua_is_mobile_ff()) {
 987             const mfe = document.getElementById("marc-form-errors");
 988             mfe.style.display = "block";
 989           }
 990         });
 991       }
 992
 993     </script>
 994   </body>
 995 </html>