Salesforce4U

I have faced some requirement in my development work . User must be able to select all the record in the page block table in one click . So I added header check-box  in page block table .  Here is the code how I achieved this. Only Java Script code I have used . This is the my page <apex:page controller="ControllerforheaderCheckboxinPBT">     <script type="text/javascript">                  function checkAll(cb){             var inputElem = document.getElementsByTagName("input");             for(var i=0; i<inputElem.length; i++){                 if(inputElem[i].id.indexOf("checkedone")!=-1)                     inputElem[i].checked = cb.checked;             }         }  ...