trim() function doesn't work in IE8?

Question

Whenever I use the trim() function on a string, it works fine with Chrome and Firefox but I get an error in IE8 saying :

Object doesn\'t

Answer 1

Internet Explorer only started support for trim() from version 9.

For reference, the MDN Polyfill for String.prototype.trim() is:

if (!String.prototype.trim) {
  (function() {
    // Make sure we trim BOM and NBSP
    var rtrim = /^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g;
    String.prototype.trim = function() {
      return this.replace(rtrim, '');
    };
  })();
}

and the support for it is:

+--------+---------+----+-------+--------+
| Chrome | Firefox | IE | Opera | Safari |
+--------+---------+----+-------+--------+
| All    | 3.5     |  9 | 10.5  |      5 |
+--------+---------+----+-------+--------+