First attempt at creating a first-run page

firstRun.js

 var backgroundPage = chrome.extension.getBackgroundPage();
 var require = backgroundPage.require;
 var Prefs = require("prefs").Prefs;
 var Utils = require("utils").Utils;
 
 function init()
 {
+  // Choose a share text variant randomly
+  var variant = Math.floor(Math.random() * 2) + 1;
+  document.documentElement.setAttribute("share-variant", variant);
+
   // Set up page title
   var titleId = (backgroundPage.isFirstRun ? "firstRun_title_install" : "firstRun_title_update");
   var pageTitle = chrome.i18n.getMessage(titleId);
-  document.title = document.getElementById("title").textContent = pageTitle;
+  document.title = document.getElementById("title-main").textContent = pageTitle;
+
+  // Only show changelog link on the update page
+  if (backgroundPage.isFirstRun)
+    document.getElementById("title-changelog").style.display = "none";
 
   // Set up URLs
-  var versionID = chrome.app.getDetails().version.split(".").slice(0, 2).join("");
-  setLinks("improvementsFeature", "https://adblockplus.org/releases/adblock-plus-" + versionID + "-for-google-chrome-released");
-  setLinks("acceptableAdsExplanation", getDocLink("acceptable_ads"),
-           getDocLink("acceptable_ads", "criteria"), backgroundPage.openOptions);
+  var versionId = chrome.app.getDetails().version.split(".").slice(0, 2).join("");
+  setLinks("title-changelog", "https://adblockplus.org/releases/adblock-plus-" + versionId + "-for-google-chrome-released");
+  setLinks("acceptableAdsExplanation", getDocLink("acceptable_ads", "criteria"),
+      backgroundPage.openOptions);
+
+  var facebookLinks = document.getElementsByClassName("share-facebook");
+  for (var i = 0; i < facebookLinks.length; i++)
+    facebookLinks[i].href = getDocLink("facebook") + "&variant=" + variant;
+
+  var twitterLinks = document.getElementsByClassName("share-twitter");
+  for (var i = 0; i < twitterLinks.length; i++)
+    twitterLinks[i].href = getDocLink("twitter") + "&variant=" + variant;
+
+  var donateLink = document.getElementById("share-donate");
+  donateLink.href = getDocLink("donate") + "&variant=" + variant;
 }
 window.addEventListener("load", init, false);
 
 function setLinks(id)
 {
   var element = document.getElementById(id);
   if (!element)
     return;
 
   var links = element.getElementsByTagName("a");
@@ skipping 11 matching lines @@
     }
   }
 }
 
 function getDocLink(page, anchor)
 {
   return Prefs.documentation_link
               .replace(/%LINK%/g, page)
               .replace(/%LANG%/g, Utils.appLocale) + (anchor ? "#" + anchor : "");
 }