function UnCheckAll(form)
{
    for (var i=0;i<form.elements.length;i++)
    {
        var e = form.elements[i];
        if(e.type=="checkbox")
            e.checked=false;
    }
}
function CheckAll(form)
{
    for (var i=0;i<form.elements.length;i++)
    {
        var e = form.elements[i];
        if(e.type=="checkbox")
           e.checked=form.chkAll.checked;
    }
}