That work!

 

By the way, I added more code!

 

<script type="text/javascript" language="javascript">
function Update_sel_protocol (src)
{
 var found=false;
 for(var i=0;i<sel_protocol.options.length;i++)
 {
  var val=sel_protocol.options(i).value;
  if(src.substr(0,val.length).toLowerCase()==val)
  {
   if(sel_protocol.selectedIndex!=i)
    sel_protocol.selectedIndex=i;
   found=true;
   break;
  }
 }
 //set others
 if(!found)
 {
  sel_protocol.selectedIndex=0;
  inp_src.value="http://";
  inp_target.selectedIndex=1;
  }
}
</script>

 

and, I disabled "browse" button also using below code.

 

<button id="btnbrowse" class="CuteEditorButtonDisabled" disabled>[[Browse]]</button>