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: it's transit equity y'all
  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       svg {
  35         /* Set the height to 100% of the screen, which we'll keep; and the
  36          * initial position to (0,0), which we're going to change
  37          * every time the window is resized, because the exact amount
  38          * that we have to slide the SVG to the left to get the ticket
  39          * into the center will change. */
  40         position: fixed;
  41         top: 0;
  42         left: 0;
  43         height: 100%;
  44
  45         /* Hide everything by default. We only show it once the user has
  46          * submitted the menu form */
  47         display: none;
  48       }
  49
  50       /* The blinking fade in/out animation for the ticket date and time */
  51       @keyframes blink {
  52         25% { opacity: 0.5; }
  53         50% { opacity: 0;   }
  54         75% { opacity: 0.5; }
  55       }
  56
  57       #tickettime, #ticketdate {
  58         /* 300 two-second blinks is ten minutes */
  59         animation: blink 2s linear 300;
  60       }
  61
  62       /* Define, load, and specify the custom font we use for the ticket
  63        * date, time, and service name. */
  64       @font-face {
  65         font-family: "CharmBypass Regular";
  66         src:
  67           url("data:font/woff2;base64,@CBPREGULAR@") format("woff2")
  68       }
  69
  70       #origindest, #servicename, #tickettime, #ticketdate, #codetext, #zone {
  71         font-family: "CharmBypass Regular", sans-serif;
  72       }
  73
  74       @font-face {
  75         font-family: "CharmBypass Bold";
  76         src:
  77           url("data:font/woff2;base64,@CBPBOLD@") format("woff2")
  78       }
  79
  80       #serviceid {
  81         font-family: "CharmBypass Bold", sans-serif;
  82       }
  83
  84       /************************/
  85       /* Scrolling animations */
  86       /************************/
  87
  88       /* Bus */
  89       @keyframes busroll {
  90         from { transform: translateX(0%);    }
  91         to   { transform: translateX(-100%); }
  92       }
  93
  94       #bus {
  95         animation: busroll 23s linear infinite;
  96       }
  97
  98
  99       /* Tram */
 100       @keyframes tramroll {
 101         from { transform: translateX(0%);   }
 102         to   { transform: translateX(100%); }
 103       }
 104
 105       #tram {
 106         animation: tramroll 17s linear infinite;
 107       }
 108
 109
 110       /* Train */
 111       @keyframes trainroll {
 112         from { transform: translateX(0%);   }
 113         to   { transform: translateX(100%); }
 114       }
 115
 116       #train {
 117         animation: trainroll 11s linear infinite;
 118       }
 119
 120
 121       /* Clouds */
 122       @keyframes cloudsfloat {
 123         from { transform: translateX(0%);   }
 124         to   { transform: translateX(-50%); }
 125       }
 126
 127       #clouds {
 128         animation: cloudsfloat 40s linear infinite;
 129       }
 130
 131       @keyframes cloudscopyfloat {
 132         from { transform: translateX(0%);   }
 133         to   { transform: translateX(-50%); }
 134       }
 135
 136       #cloudscopy {
 137         animation: cloudscopyfloat 40s linear infinite;
 138       }
 139
 140
 141       /* Trees */
 142       @keyframes treespass {
 143         from { transform: translateX(0%);   }
 144         to   { transform: translateX(-50%); }
 145       }
 146
 147       #trees {
 148         /* The trees move a little faster than the clouds */
 149         animation: treespass 30s linear infinite;
 150       }
 151
 152       @keyframes treescopypass {
 153         from { transform: translateX(0%);   }
 154         to   { transform: translateX(-50%); }
 155       }
 156
 157       #treescopy {
 158         /* The trees move a little faster than the clouds */
 159         animation: treescopypass 30s linear infinite;
 160       }
 161
 162
 163       /* City skyline */
 164       @keyframes cityscroll {
 165         from { transform: translateX(0%);   }
 166         to   { transform: translateX(-50%); }
 167       }
 168
 169       #city {
 170         /* The city moves faster than the clouds but slower
 171          * than the trees */
 172         animation: cityscroll 35s linear infinite;
 173       }
 174
 175       @keyframes citycopyscroll {
 176         from { transform: translateX(0%);   }
 177         to   { transform: translateX(-50%); }
 178       }
 179
 180       #citycopy {
 181         /* The city moves faster than the clouds but slower
 182          * than the trees */
 183         animation: citycopyscroll 35s linear infinite;
 184       }
 185     </style>
 186   </head>
 187
 188   <body>
 189     <div id="menu">
 190       <h1>CharmBypass</h1>
 191       <h2>it's transit equity y'all</h2>
 192
 193       <p>
 194         <em>Hint:</em> If they start checking it, the daily security
 195         code stays the same all day and is the same on a $2 bus ticket
 196         as it is on a $9 MARC ticket. It's also the same on every phone.
 197       </p>
 198
 199       <form>
 200         <fieldset>
 201           <legend>Local Bus, Light Rail, or Metro</legend>
 202           <div>
 203             <label for="code1">
 204               Daily security code (optional):
 205             </label>
 206             <input id="code1"
 207                    name="code"
 208                    type="text"
 209                    size="2"
 210                    minlength="2"
 211                    maxlength="2"
 212                    pattern="[a-zA-Z0-9]*" />
 213           </div>
 214           <input type="hidden" name="servicename" value="BaltimoreLink" />
 215           <input type="submit" name="go" value="Generate Ticket" />
 216         </fieldset>
 217       </form>
 218       <form>
 219         <fieldset>
 220           <legend>Commuter Bus</legend>
 221           <input type="hidden" name="serviceid" value="R" />
 222           <input type="hidden" name="servicename" value="Commuter Bus" />
 223
 224           <div>
 225             <label for="code2">
 226               Daily security code (optional):
 227             </label>
 228             <input id="code2"
 229                    name="code"
 230                    type="text"
 231                    size="2"
 232                    minlength="2"
 233                    maxlength="2"
 234                    pattern="[a-zA-Z0-9]*" />
 235           </div>
 236
 237           <p>Zone:</p>
 238           <div>
 239             <input type="radio" required
 240                    name="zone"
 241                    id="zone1"
 242                    value="Zone 1" />
 243             <label for="zone1">Zone 1</label>
 244           </div>
 245           <div>
 246             <input type="radio" required
 247                    name="zone"
 248                    id="zone2"
 249                    value="Zone 2" />
 250             <label for="zone2">Zone 2</label>
 251           </div>
 252           <div>
 253             <input type="radio" required checked
 254                    name="zone"
 255                    id="zone3"
 256                    value="Zone 3" />
 257             <label for="zone3">Zone 3</label>
 258           </div>
 259           <div>
 260             <input type="radio" required
 261                    name="zone"
 262                    id="zone4"
 263                    value="Zone 4" />
 264             <label for="zone4">Zone 4</label>
 265           </div>
 266           <div>
 267             <input type="radio" required
 268                    name="zone"
 269                    id="zone5"
 270                    value="Zone 5" />
 271             <label for="zone5">Zone 5</label>
 272           </div>
 273
 274           <input type="submit" name="go" value="Generate Ticket" />
 275         </fieldset>
 276       </form>
 277       <form>
 278         <fieldset>
 279           <legend>MARC Train</legend>
 280
 281           <div>
 282             <label for="code3">
 283               Daily security code (optional):
 284             </label>
 285             <input id="code3"
 286                    name="code"
 287                    type="text"
 288                    size="2"
 289                    minlength="2"
 290                    maxlength="2"
 291                    pattern="[a-zA-Z0-9]*" />
 292           </div>
 293
 294           <p>Origin:</p>
 295           <div>
 296             <input type="radio" required checked
 297                    name="origin"
 298                    id="origin1"
 299                    value="BAL" />
 300             <label for="origin1">Baltimore/Penn (Penn Line)</label>
 301           </div>
 302           <div>
 303             <input type="radio" required
 304                    name="origin"
 305                    id="origin2"
 306                    value="BCA" />
 307             <label for="origin2">Baltimore/Camden (Camden Line)</label>
 308           </div>
 309           <div>
 310             <input type="radio" required
 311                    name="origin"
 312                    id="origin3"
 313                    value="BWE" />
 314             <label for="origin3">Bowie State (Penn Line)</label>
 315           </div>
 316           <div>
 317             <input type="radio" required
 318                    name="origin"
 319                    id="origin4"
 320                    value="BWI" />
 321             <label for="origin4">BWI Airport (Penn Line)</label>
 322           </div>
 323           <div>
 324             <input type="radio" required
 325                    name="origin"
 326                    id="origin5"
 327                    value="CPK" />
 328             <label for="origin5">College Park (Camden Line)</label>
 329           </div>
 330           <div>
 331             <input type="radio" required
 332                    name="origin"
 333                    id="origin6"
 334                    value="SEB" />
 335             <label for="origin6">Seabrook (Penn Line)</label>
 336           </div>
 337           <div>
 338             <input type="radio" required
 339                    name="origin"
 340                    id="origin7"
 341                    value="WAS" />
 342             <label for="origin7">Washington D.C.</label>
 343           </div>
 344           <div>
 345             <input type="radio" required
 346                    name="origin"
 347                    id="origin8"
 348                    value="WBL" />
 349             <label for="origin8">West Baltimore (Penn Line)</label>
 350           </div>
 351
 352           <p>Destination:</p>
 353           <div>
 354             <input type="radio" required
 355                    name="destination"
 356                    id="destination1"
 357                    value="BAL" />
 358             <label for="destination1">Baltimore/Penn (Penn Line)</label>
 359           </div>
 360           <div>
 361             <input type="radio" required
 362                    name="destination"
 363                    id="destination2"
 364                    value="BCA" />
 365             <label for="destination2">Baltimore/Camden (Camden Line)</label>
 366           </div>
 367           <div>
 368             <input type="radio" required
 369                    name="destination"
 370                    id="destination3"
 371                    value="BWE" />
 372             <label for="destination3">Bowie State (Penn Line)</label>
 373           </div>
 374           <div>
 375             <input type="radio" required
 376                    name="destination"
 377                    id="destination4"
 378                    value="BWI" />
 379             <label for="destination4">BWI Airport (Penn Line)</label>
 380           </div>
 381           <div>
 382             <input type="radio" required
 383                    name="destination"
 384                    id="destination5"
 385                    value="CPK" />
 386             <label for="destination5">College Park (Camden Line)</label>
 387           </div>
 388           <div>
 389             <input type="radio" required
 390                    name="destination"
 391                    id="destination6"
 392                    value="SEB" />
 393             <label for="destination6">Seabrook (Penn Line)</label>
 394           </div>
 395           <div>
 396             <input type="radio" required checked
 397                    name="destination"
 398                    id="destination7"
 399                    value="WAS" />
 400             <label for="destination7">Washington D.C.</label>
 401           </div>
 402           <div>
 403             <input type="radio" required
 404                    name="destination"
 405                    id="destination8"
 406                    value="WBL" />
 407             <label for="destination8">West Baltimore (Penn Line)</label>
 408           </div>
 409
 410           <input type="hidden" name="serviceid" value="R" />
 411           <input type="hidden" name="servicename" value="MARC Train" />
 412           <input type="submit" name="go" value="Generate Ticket" />
 413         </fieldset>
 414       </form>
 415     </div>
 416
 417     @SVGDATA@
 418
 419     <script>
 420
 421       /**
 422        * Center the ticket within the browser by translating the SVG
 423        * until the ticket and the viewport centerlines coincide.
 424        */
 425       function center_ticket() {
 426         /* We're relying on the SVG being the full height of the
 427          * viewport already, and on the aspect ratio being
 428          * preserved. First, find the center of the ticket. */
 429         const r = document.getElementById("ticket").getBoundingClientRect();
 430         const c = r.left + (r.width / 2);
 431
 432         /* That's the center-line of the ticket. We want to move it to
 433          * the center-line of the viewport. */
 434         const vc = document.documentElement.clientWidth / 2;
 435
 436         /* This is how much we need to translate the SVG */
 437         const hdelta = vc - c;
 438
 439         /* But before we can set the absolute left-coordinate of the
 440          * SVG, we need to know where it is now. Note: without the
 441          * "px" this doesn't default to pixels like CSS does. */
 442         const svg = document.querySelector("svg");
 443         svg.style.left = (svg.getBoundingClientRect().left + hdelta) + "px";
 444       }
 445
 446
 447       /**
 448        * Set the service identifier from the querystring if it's there.
 449        * Otherwise, leave it at the default of "F".
 450        */
 451       function set_service_id() {
 452         const sid = document.getElementById("serviceid");
 453
 454         /* Get the "serviceid" from the querystring if it's there */
 455         const params = new URLSearchParams(document.location.search);
 456         if (params.get("serviceid")) {
 457           sid.textContent = params.get("serviceid");
 458         }
 459       }
 460
 461
 462       /**
 463        * Set the service name from the querystring if it's there.
 464        * Otherwise, leave it at the default of "BaltimoreLink".
 465        */
 466       function set_service_name() {
 467         const sid = document.getElementById("servicename");
 468
 469         /* Get the "servicename" from the querystring if it's there */
 470         const params = new URLSearchParams(document.location.search);
 471         if (params.get("servicename")) {
 472           sid.textContent = params.get("servicename");
 473         }
 474       }
 475
 476
 477       /**
 478        * Set the zone from the given "zone" parameter and then unhide it.
 479        */
 480       function set_zone(zone) {
 481         const z = document.getElementById("zone");
 482
 483         z.textContent = zone;
 484         z.style.display = "block"; /* hidden by default */
 485       }
 486
 487
 488       /**
 489        * Resize the  ticket background based on the service name.
 490        * The BaltimoreLink, Commuter Bus, and MARC Train tickets
 491        * are all different heights and are arranged vertically a
 492        * bit different.
 493        *
 494        * Rather than design three completelty separate tickets and
 495        * then have to keep track of which one we're using, I have
 496        * instead decided to use one ticket and to reposition it
 497        * on-the-fly based on the service name. This is necessarily
 498        * a bit ugly because it involves a lot of magic numbers that
 499        * can only be explained if you open up inkscape with a CharmPass
 500        * screenshot to see where things belong and how to get them there.
 501        *
 502        * The SVG was designed with BaltimoreLink in mind, so this
 503        * is a no-op if the service is BaltimoreLink.
 504        */
 505       function resize_ticket() {
 506         /* Get the "servicename" from the querystring if it's there */
 507         const params = new URLSearchParams(document.location.search);
 508         const tbg = document.getElementById("ticketbg");
 509         const t = document.getElementById("ticket");
 510         const sn = document.getElementById("servicename");
 511
 512         if (params.get("servicename") === "Commuter Bus") {
 513           /* The top of the background is initially at y=246.859, and
 514            * we scale it by a factor of 1.12 to y=276.482 for a change
 515            * of 29.623. So after we scale it, we translate it upwards
 516            * by that amount to put it back where it started. */
 517           tbg.setAttribute("transform", "translate(0 -29.623) scale(1 1.12)");
 518
 519           /* Now translate the entire ticket up by the magic amount, 1/5
 520            * of the size change we made to the background. This ratio
 521            * was found by measuring pixels in side-by-side screenshots
 522            * of BaltimoreLink and Commuter Bus tickets. */
 523           t.setAttribute("transform", "translate(0 -9.33)");
 524
 525           /* More magic numbers discovered by comparing the two
 526            * tickets overlayed in inkscape */
 527           sn.setAttribute("transform", "translate(0 64.28)");
 528         }
 529         else if (params.get("servicename") === "MARC Train") {
 530           /* insane tricks are explained above */
 531           tbg.setAttribute("transform",
 532                            "translate(0 -72.378) scale(1 1.2932)");
 533           t.setAttribute("transform", "translate(0 -67.17)");
 534           sn.setAttribute("transform", "translate(0 131.0)");
 535         }
 536       }
 537
 538
 539       /**
 540        * Set the security code from the querystring if it was given;
 541        * otherwise generate a random code.
 542        */
 543       function set_code() {
 544         const ct = document.getElementById("codetext");
 545
 546         /* Get the "code" from the querystring if it's there */
 547         const params = new URLSearchParams(document.location.search);
 548         if (params.get("code")) {
 549           ct.textContent = params.get("code").toUpperCase();
 550         }
 551         else {
 552           /* Otherwise, use a random code */
 553           const bucket = ["0","1","2","3","4","5","6","7","8","9",
 554                           "A","B","C","D","E","F","G","H","I","J",
 555                           "K","L","M","N","O","P","Q","R","S","T",
 556                           "U","V","W","X","Y","Z"];
 557
 558           /* Two random ints between 0 and 35 */
 559           const i1 = Math.floor(Math.random() * 36);
 560           const i2 = Math.floor(Math.random() * 36);
 561           const d1 = bucket[i1];
 562           const d2 = bucket[i2];
 563           ct.textContent = d1 + d2;
 564         }
 565       }
 566
 567
 568       /**
 569        * Center the security code within its container.
 570        *
 571        * Some codes like "II" and "WW" can take up wildly different
 572        * amounts of horizonetal space, but they should always be
 573        * centered inside their little red box. This turns out to be
 574        * harder than it sounds because we can only find the width of
 575        * the code in browser coordinates, whereas its "x" coordinate
 576        * is in SVG coordinates. Anyway, we do it.
 577        */
 578       function center_code() {
 579         /* Center the security code inside its red box */
 580         const ct = document.getElementById("codetext");
 581         const bg = document.getElementById("codebg");
 582
 583         /* First, find the center of the red box */
 584         const r1 = bg.getBoundingClientRect();
 585         const c1 = r1.left + (r1.width / 2);
 586
 587         /* Now the center of the code text */
 588         const r2 = ct.getBoundingClientRect();
 589         const c2 = r2.left + (r2.width / 2);
 590
 591         /* What do we add to c2 to make it equal to c1? */
 592         const hdelta = c1 - c2;
 593
 594         /* We've measured everything so far in "client rect"
 595          * coordinates, because that's the only available measurement
 596          * we have for the width of the <text> element. But when we
 597          * reposition that <text> element, it will be by adjusting its
 598          * "x" attribute, and that attribute uses a different coordinate
 599          * system than the client rect does. Specifically, "x" refers to
 600          * an offset within the SVG's coordinate system, and the client
 601          * rect coordinates are pixels on-screen. To convert between the
 602          * two, we can take the "width" attribute of the background
 603          * element and compare it to the width of the background
 604          * element's client rect. Since the size of the background is
 605          * fixed, this should give us a multiplier that turns client rect
 606          * distances (what we have) into SVG distances (what we want) */
 607         const client_to_svg = parseFloat(bg.getAttribute("width"))/r1.width;
 608
 609         /* Convert hdelta from client rect to SVG coordinates */
 610         const svg_hdelta = hdelta * client_to_svg;
 611
 612         /* Since this <text> element has an "x" attribute it's easier for
 613          * us to shift that than it is to mess with the "left" style. */
 614         ct.setAttribute("x", parseFloat(ct.getAttribute("x")) + svg_hdelta);
 615       }
 616
 617       /**
 618        * Set the ticket's expiration date and time.
 619        *
 620        * BaltimoreLink and MARC Train tickets expire after 90 minutes;
 621        * while Commuter Bus tickets expire after 10 minutes.
 622        */
 623       function set_ticket_expiry() {
 624         /* There are two parameters, time and date, that we store in one
 625          * underlying "date" variable. */
 626         const date = new Date();
 627
 628         /* BaltimoreLink and MARC Train */
 629         let minutes = 90;
 630         const params = new URLSearchParams(document.location.search);
 631         if (params.get("servicename") === "Commuter Bus") {
 632           /* Commuter bus tickets are only valid for ten minutes */
 633           minutes = 10;
 634         }
 635
 636         /* We use the low-level get/setTime to change the number of
 637          * milliseconds since the epoch that this date represents
 638          * Obviously correct, and avoids all suspicious corner cases
 639          * for a few more decades. */
 640         date.setTime(date.getTime() + (minutes*60*1000));
 641
 642         tt = document.getElementById("tickettime");
 643         tt.textContent = date.toLocaleTimeString();
 644
 645         const td = document.getElementById("ticketdate");
 646         const dateopts = {
 647           day: "2-digit",
 648           month: "2-digit",
 649           year: "2-digit"
 650         };
 651         td.textContent = date.toLocaleDateString("en-US", dateopts);
 652       }
 653
 654
 655       /**
 656        * Swap the day/night sky colors.
 657        *
 658        * We use CSS classes to keep track of the current state because
 659        * it's a tiny bit cleaner than a global variable, but for some
 660        * reason we can't use those same classes to actually change the
 661        * color. (The classes, change, but the color doesn't.) Rather
 662        * than waste time trying to explain this, we just set the "fill"
 663        * attribute ourselves whenever we swap classes.
 664        */
 665       function swap_day_night() {
 666         const sky = document.getElementById("sky");
 667
 668         if (sky.getAttribute("class") === "night") {
 669           sky.setAttribute("fill", "#efb02f");
 670           sky.setAttribute("class", "day");
 671         }
 672         else {
 673           /* Put this case second so that the first time the
 674            * screen is tapped (when there are no classes on
 675            * the sky element) the color still changes. */
 676           sky.setAttribute("fill", "#143b66");
 677           sky.setAttribute("class", "night");
 678         }
 679       }
 680
 681
 682       /**
 683        * Compute the zone (string) for the given origin/destination pair.
 684        *
 685        * If we don't know it or if you chose in invalid pair (destination
 686        * not on the same line as your origin?) then null is returned.
 687        */
 688       function compute_marc_zone(src, dest) {
 689
 690         /* Sorted on the first component, then the second */
 691         const zone_map = {
 692           BAL_BWE: 2,
 693           BAL_BWI: 1,
 694           BAL_SEB: 3,
 695           BAL_WAS: 4,
 696           BAL_WBL: 1,
 697           BCA_CPK: 3,
 698           BCA_WAS: 4,
 699           BWE_BWI: 1,
 700           BWE_SEB: 1,
 701           BWE_WAS: 2,
 702           BWE_WBL: 2,
 703           BWI_WAS: 3,
 704           BWI_WBL: 1
 705         };
 706
 707         /* Forward direction key for zone_map */
 708         const fwd = src + "_" +  dest;
 709
 710         /* Reverse direction key for zone_map. The zone_map only
 711          * has them listed in one direction, so we check both
 712          * directions here. */
 713         const rev = dest + "_" +  src;
 714
 715         /* The default. Obviously wrong for when we don't
 716          * have the necessary data. */
 717         let zone = -1;
 718
 719         if (zone_map[fwd]) {
 720           zone = zone_map[fwd];
 721         }
 722         else if (zone_map[rev]) {
 723           zone = zone_map[rev];
 724         }
 725
 726         /* Convert the number to a string */
 727         switch (zone) {
 728           case 1:
 729             return "One Zone";
 730           case 2:
 731             return "Two Zone";
 732           case 3:
 733             return "Three Zone";
 734           case 4:
 735             return "Four Zone";
 736           default:
 737             return null;
 738         }
 739       }
 740
 741
 742       /**
 743        * Compute and set the zone.
 744        *
 745        * We can be given a zone in two ways. First, on Commuter Bus
 746        * tickets, it is given explicitly via the querystring. But
 747        * It can also be specified implicitly via the origin and
 748        * destination on a MARC Train ticket. Here we try both and
 749        * then call set_zone() with the result if something worked.
 750        */
 751       function compute_and_set_zone() {
 752         const params = new URLSearchParams(document.location.search);
 753         const src = params.get("origin");
 754         const dest = params.get("destination");
 755
 756         if (src && dest) {
 757           /* MARC Train. We can assume that compute_marc_zone() doesn't
 758            * return null because that's part of our form validation. */
 759           const zone = compute_marc_zone(src, dest);
 760           set_zone(zone);
 761         }
 762         else if (params.get("zone")) {
 763           /* Commuter Bus */
 764           set_zone(params.get("zone"));
 765         }
 766       }
 767
 768
 769       /**
 770        * Set the origin and destination for the MARC Train if they
 771        * were provided, and unhide them if so.
 772        */
 773       function set_marc_origin_destination() {
 774         const params = new URLSearchParams(document.location.search);
 775         if (!params.get("origin") || !params.get("destination")) {
 776           return;
 777         }
 778
 779         const src = params.get("origin");
 780         const dest = params.get("destination");
 781
 782         /* origindest contains both the origin and destination */
 783         const origindest = document.getElementById("origindest");
 784
 785         const origin = document.getElementById("origin");
 786         const destination = document.getElementById("destination");
 787
 788         origin.textContent = params.get("origin");
 789         destination.textContent = params.get("destination");
 790
 791         origindest.style.display = "block"; /* hidden by default */
 792       }
 793
 794
 795       /**
 796        * Hide the menu and display the ticket. This is what happens
 797        * when you submit the form.
 798        */
 799       function go() {
 800         /* To create our "window" onto the scene, we're going to slide the
 801          * SVG off the left-hand side of the screen, and we don't want
 802          * scroll bars to appear. */
 803         document.body.style.overflow = "hidden";
 804         document.body.style.margin = "0";
 805         document.body.style.padding = "0";
 806
 807         const svg = document.querySelector("svg");
 808         const menu = document.getElementById("menu");
 809         svg.style.display = "initial";
 810         menu.style.display = "none";
 811       }
 812
 813       /**
 814        * Validate the MARC form's origin/destination.
 815        *
 816        * We don't want the user to be able to choose a pair of stops that
 817        * aren't actually connected by the same MARC line. If we don't have
 818        * zone information for the (origin,destination) pair, that indicates
 819        * that it's probably not a valid choice; otherwise I would have
 820        * filled in the information from the CharmPass app already.
 821        */
 822       function validate_origin_destination(event) {
 823         const origins = document.getElementsByName("origin");
 824         const destinations = document.getElementsByName("destination");
 825
 826         let src = null;
 827         let dest = null;
 828         origins.forEach((x) => { if (x.checked) src = x; })
 829         destinations.forEach((x) => {
 830           if (x.checked) dest = x;
 831
 832           /* clear all errors before possibly setting one */
 833           x.setCustomValidity('');
 834         })
 835
 836         if (src.value === dest.value) {
 837           let err = "Origin and destination are the same!";
 838           dest.setCustomValidity(err);
 839         }
 840         else if (compute_marc_zone(src.value, dest.value) === null) {
 841           let err = "Origin and destination are on different lines!";
 842           dest.setCustomValidity(err);
 843         }
 844       }
 845
 846       /*****************************************************/
 847       /* Add event handlers for all of the functions above */
 848       /*****************************************************/
 849
 850       const params = new URLSearchParams(document.location.search);
 851       if (params.get("go")) {
 852         /* First unhide the SVG (swap it with the form) */
 853         window.addEventListener("load", go);
 854
 855         /* Center the ticket once when the page has loaded */
 856         window.addEventListener("load", center_ticket);
 857
 858         /* Re-center the ticket when the window is resized */
 859         window.addEventListener("resize", center_ticket);
 860
 861         /* Set the service identifier when the page has loaded */
 862         window.addEventListener("load", set_service_id);
 863
 864         /* Set the service name when the page has loaded */
 865         window.addEventListener("load", set_service_name);
 866
 867         /* Resize the ticket background if necessary */
 868         window.addEventListener("load", resize_ticket);
 869
 870         /* Set the security code text when the page has loaded */
 871         window.addEventListener("load", set_code);
 872
 873         /* Center the security code text when the page has loaded; in
 874          * particular, after we set the code. */
 875         window.addEventListener("load", center_code);
 876
 877         /* Set the ticket expiration date/time upon page load */
 878         window.addEventListener("load", set_ticket_expiry);
 879
 880         /* Set the MARC Train origin and destination, if applicable */
 881         window.addEventListener("load", set_marc_origin_destination);
 882
 883         /* Compute and set the zone, if applicable */
 884         window.addEventListener("load", compute_and_set_zone);
 885
 886         /* Swap colors when the screen is tapped */
 887         document.body.addEventListener("click", swap_day_night);
 888       }
 889       else {
 890         /* If we haven't submitted the form yet, set up change handlers
 891          * for the origin/destination radio buttons that validate that
 892          * the origin and destination are on the same line. */
 893         document.getElementsByName("origin").forEach(
 894          (x) => x.addEventListener("change", validate_origin_destination)
 895         );
 896         document.getElementsByName("destination").forEach(
 897          (x) => x.addEventListener("change", validate_origin_destination)
 898         );
 899
 900         /* Also do it when the page loads, because firefox likes to
 901          * remember your selection even after the page reloads. */
 902         window.addEventListener("load", validate_origin_destination);
 903       }
 904
 905     </script>
 906   </body>
 907 </html>