Issue #1995314 by sgerrand: Fixed Access method on regex string fails in IE7+ browsers.

clientside_validation.js

@@ -899,7 +899,7 @@
           var result = true;
           for (var i = 0; i < param.expressions.length; i++) {
             var reg = param.expressions[i];
-            var delim = reg.lastIndexOf(reg[0]);
+            var delim = reg.lastIndexOf(reg.charAt(0));
             // Only allow supported modifiers
             var modraw = reg.substr(delim + 1) || '';
             var mod = '';