String.prototype.trim = _trim;

function _trim()
{
var start = 0;
var end = 1;

 while(this.charAt(start) == " ") start++;
 while(this.charAt(this.length - end) == " ") end++;
 if (this.length == (end-1)) {
   return "";
 } else {
   return this.substring(start, this.length - end + 1);
 }
}