The following is a very nice solution to remove all leading white spaces in a String, it uses the prototype functionality to add a method trimLeading to the String class:

  <script type="text/javascript">

    String.prototype.trimLeading=trimLeading;
 
    function trimLeading() {               
      return this.replace(/^\s+/,'');
    }

  </script>

You can use this new function in the following way:

  <script type="text/javascript">

    var text = "   HELLO";
    alert(text.trimLeading());

  </script>