Regarding jquery select tag

I'开发者_StackOverflowm using struts2 and jQuery.

Following is my code written in JSP:

<s:select o name="mfgDimensions" list="{'Product','Station','Test','AssemblyLine','Operator','Debug Mode'}" multiple="true" headerKey="" headerValue="Manufacturing Dimensions" size="3"/>

I want when user will going to select header value (i.e in my case "Manufacturing Dimensions") the value will not be get selectable...

can it be possible with jquery or any other way??

Thanks kris

    <s:select id="dimension" name="mfgDimensions" list="{'Product','Station','Test','AssemblyLine','Operator','Debug Mode'}" multiple="true" headerKey="" headerValue="Manufacturing Dimensions" size="3"/
onchange="check_value(this.value)"/>


function check_value(value){
if(value=="Manufacturing Dimensions")
  document.getElementById("dimension').value='';
}