String.prototype.trim = function() {
    return this.replace(/(^\s*)|(\s*$)/g, "");
}

/**
 * returns string with all leading and trailing characters 
 * eliminated.
 */
function trim(str){
  var s = new String(str);
  //trailing spaces
  while (s.length>0 && isSpaceCharacter(""+s.charAt(s.length-1))){
    s = s.substring(0,s.length-1);
  }
  //leading spaces
  while (s.length>0 && isSpaceCharacter(""+s.charAt(0))){
    s = s.substring(1);
  }
  return s
}

var spaces = " \t\r\n"+String.fromCharCode(160);

function isSpaceCharacter(ch){
  return spaces.indexOf(ch) >-1;
}