I want to increase the height of the div tag on click of button. Every time a user clicks a button it should increase the height of that particular div tag, say by 200px or so..

HTML

      <div id=controls>

         <input type=button onclick=incHeight() id=btn name=btn>

      </div>

      <div id=container style=min-height:250px;> &nbsp;</div>

The below script works properly

Javascript

      <script type=text/javascript>

        function incHeight()

        {

          document.getElementById(container).style.height = 250+'px';



        }

      </script>

But I want to do something like this, which is not working. The problem I think is the 'px' portion in the value. Anybody have any idea how to extract the INT portion of the value...

      <script type=text/javascript>

        function incHeight()

        {

          document.getElementById(container).style.height += 250;     

        }

      </script>

The problem is how do I get the '250' portion of the height value neglecting the 'px' in javascript..