function checkallid(){
if(!window.myform.opid.checked){
window.myform.opid.checked=false;}
else{
window.myform.opid.checked=true;}
for(var i=0;i<window.myform.elements.length;i++){
var e = window.myform.elements[i];
if (e.name != 'chkall')
e.checked = window.myform.opid.checked;
}
}