supporting the callback after the script is fully loaded

See http://stackoverflow.com/questions/4845762/onload-handler-for-script-tag-in-internet-explorer

war/src/main/webapp/scripts/hudson-behavior.js

@@ -2064,10 +2064,43 @@ var DragDrop = function(id, sGroup, config) {
     });
 })();
 
-function loadScript(href) {
-    var s = document.createElement("script");
-    s.setAttribute("src",href);
-    document.getElementsByTagName("HEAD")[0].appendChild(s);
+/**
+ * Loads the script specified by the URL.
+ *
+ * @param href
+ *      The URL of the script to load.
+ * @param callback
+ *      If specified, this function will be invoked after the script is loaded.
+ * @see http://stackoverflow.com/questions/4845762/onload-handler-for-script-tag-in-internet-explorer
+ */
+function loadScript(href,callback) {
+    var head = document.getElementsByTagName("head")[0] || document.documentElement;
+    var script = document.createElement("script");
+    script.src = href;
+
+    if (callback) {
+        // Handle Script loading
+        var done = false;
+
+        // Attach handlers for all browsers
+        script.onload = script.onreadystatechange = function() {
+            if ( !done && (!this.readyState ||
+                    this.readyState === "loaded" || this.readyState === "complete") ) {
+                done = true;
+                callback();
+
+                // Handle memory leak in IE
+                script.onload = script.onreadystatechange = null;
+                if ( head && script.parentNode ) {
+                    head.removeChild( script );
+                }
+            }
+        };
+    }
+
+    // Use insertBefore instead of appendChild  to circumvent an IE6 bug.
+    // This arises when a base node is used (#2709 and #4378).
+    head.insertBefore( script, head.firstChild );
 }
 
 var downloadService = {