trim izquierda ( TrimLeft ) javascript

Código Javascript

<script type="text/javascript">
function TrimLeft( str ) {
	var resultStr = "";
	var i = len = 0;
	// Return immediately if an invalid value was passed in
	if (str+"" == "undefined" || str == null)	
		return null;
	// Make sure the argument is a string
	str += "";
	if (str.length == 0) 
		resultStr = "";
	else {	
  		// Loop through string starting at the beginning as long as there
  		// are spaces.
//	  	len = str.length - 1;
		len = str.length;
		
  		while ((i <= len) && (str.charAt(i) == " "))
			i++;
   	// When the loop is done, we're sitting at the first non-space char,
 		// so return that char plus the remaining chars of the string.
  		resultStr = str.substring(i, len);
  	}
  	return resultStr;
}
</SCRIPT>