Javascript Array toCommaSeparatedString()

Array.prototype.toCommaSeparatedString = function() {

 if (this.length > 0) {

  if (this.length == 1) {

   return "" + this[0];
  } else {/* w w w  .  jav  a2  s .c o m*/

   var buf = new StringBuilder();
   for ( var i = 0; i < this.length; i++) {
    if (i > 0) {
     buf.append(",");
    }

    buf.append(this[i]);
   }
   return buf.toString();
  }
 }

 return null;

};