user selection: Make inserting the search term into lang strings in JavaScript more robust.

user/selector/lib.php

@@ -471,8 +471,8 @@ abstract class user_selector_base {
 
         // Initialise the selector.
         $output .= print_js_call('new user_selector', array($this->name, $hash,
-                sesskey(), $this->extrafields, get_string('previouslyselectedusers'),
-                get_string('nomatchingusers')), true);
+                sesskey(), $this->extrafields, get_string('previouslyselectedusers', '', '%%SEARCHTERM%%'),
+                get_string('nomatchingusers', '', '%%SEARCHTERM%%')), true);
         return $output;
     }
 }

user/selector/script.js

@@ -283,7 +283,7 @@ user_selector.prototype.handle_selection_change = function() {
 
 // Methods for refreshing the list of displayed options ========================
 user_selector.prototype.insert_search_into_str = function(string, search) {
-    return string.replace("''", "'" + search + "'");
+    return string.replace("%%SEARCHTERM%%", search);
 }
 
 /**