Adopts Prezi URL check to match default share links.

prezi.js

                             else {
                                 var presIdTmp = urlValue.substring(
                                         urlValue.indexOf("prezi.com/") + 10);
-                                if (!Util.isAlphanumeric(presIdTmp)
+                                if (!isAlphanumeric(presIdTmp)
                                         || presIdTmp.indexOf('/') < 2) {
                                     $.prompt.goToState('state1');
                                     return false;
         }
     };
 
+    /**
+     * Indicates if the given string is an alphanumeric string.
+     * Note that some special characters are also allowed (-, _ , /, &, ?, =, ;) for the
+     * purpose of checking URIs.
+     */
+    function isAlphanumeric(unsafeText) {
+        var regex = /^[a-z0-9-_\/&\?=;]+$/i;
+        return regex.test(unsafeText);
+    }
+
     /**
      * Returns the presentation id from the given url.
      */

util.js

         return $('<div/>').text(unsafeText).html();
     };
 
-    /**
-     * Indicates if the given string is an alphanumeric string.
-     * Note that some special characters are also allowed (-, _ , /) for the
-     * purpose of checking URIs. (FIXME: This should maybe moved to another not
-     * so generic method in the future.)
-     */
-    my.isAlphanumeric = function(unsafeText) {
-        var regex = /^[a-z0-9-_\/]+$/i;
-        return regex.test(unsafeText);
-    };
-
     /**
      * Returns the available video width.
      */