function selectAll(formid)
{
   for(i= 0; i < document.getElementById(formid).length; i++)
   {
	  if(document.getElementById(formid)[i].type == 'checkbox')
	  {
	     if(document.getElementById(formid)[i].checked)
		  document.getElementById(formid)[i].checked = false;
		 else
		  document.getElementById(formid)[i].checked = true;
	  }
   }
}