[Contributed by luke]

Access key hints are now added with Javascript, and are tailored appropriately to the platform (Ctrl for Macs, Alt for Windows).

Thanks, Luke!


git-svn-id: http://www.rousette.org.uk/svn/tracks-repos/trunk@152 a4c988fc-2ded-0310-b66e-134b36920a42

tracks/public/javascripts/accesskey-hints.js

@@ -0,0 +1,90 @@
+/*
+ * AccessKey Hints
+ *
+ * Checks all HTML elements on this page that can have an accesskey attribute
+ * (<a>, <area>, <button>, <input>, <label>, <legend> and <textarea>)
+ * and creates or appends the title attribute to include platform-specific
+ * hint in the title, i.e. "Alt+S" (Win)
+ * or "Ctrl+S)" (Mac). If a title exists, a space plus the hint wrapped in
+ * parentheses is appended. The only exception is if the title already contains
+ * 'accesskey', 'Alt+' or 'Ctrl+' (case-insensitive) in which case this script
+ * will leave it alone.
+ *
+ *  Use the following markup to include the library:
+ *  <script type="text/javascript" src="access-key-hints.js"></script>
+ */
+
+addEvent(window, "load", addAccessKeyHints);
+
+function addAccessKeyHints()
+{
+  var elemTypes = new Array('a','area','button','input','label','legend','textarea');
+  for(var i = 0; i < elemTypes.length; i++)
+  {
+    addHint(document.getElementsByTagName(elemTypes[i]));
+  }
+}
+
+function addHint(elems)
+{
+  var elem;
+  var i = 0;
+
+  processElements:
+  while(elem = elems.item(i++))
+  {
+    var accessKey = elem.getAttributeNode("accesskey");
+    if (!accessKey || !accessKey.value)
+      continue processElements;
+
+    var title = elem.getAttributeNode("title");
+    if (title && title.value)
+    {
+      var overrides = new Array('accesskey','alt+','ctrl+');
+      for (var j=0; j < overrides.length; j++)
+      {
+        if (title.value.toLowerCase().indexOf(overrides[j]) != -1)
+          continue processElements;
+      }
+      elem.setAttribute("title", title.value + ' (' + getHintText(accessKey.value) + ')');
+    }
+    else
+    {
+        elem.setAttribute("title", getHintText(accessKey.value));
+    }
+  }
+}
+
+function getHintText(accessKey)
+{
+        return getModifier() + '+' + accessKey.toUpperCase();
+}
+
+function getModifier()
+{
+   var ua = navigator.userAgent.toLowerCase(); 
+   if (ua.indexOf('mac') == -1)
+     return 'Alt';
+   else
+     return 'Ctrl';
+}
+
+// This is a cross-browser function for event addition.
+function addEvent(obj, evType, fn)
+{
+  if (obj.addEventListener)
+  {
+    obj.addEventListener(evType, fn, false);
+    return true;
+  }
+  else if (obj.attachEvent)
+  {
+    var r = obj.attachEvent("on" + evType, fn);
+    return r;
+  }
+  else
+  {
+    alert("Event handler could not be attached");
+    return false;
+  }
+}