clear check boxes

    echo '<script>

        function uncheck(){
            var a=uncheck.arguments,z0=0;
            for (;z0<a.length;z0++){
                document.getElementById(a[z0])?document.getElementById(a[z0]).checked=false:null;
            }
        }

        </script>';


    echo '<input type="checkbox" id="addfile1" onClick="uncheck(\'clearAll\');" name="fileck1" value="1">Instructions<br>';


    echo '<input type="checkbox" id="addfile2" onClick="uncheck(\'clearAll\');" name="fileck2" value="1">Wiring Diagram<br>';


    echo '<input type="checkbox" id="addfile3" onClick="uncheck(\'clearAll\');" name="fileck3" value="1">File 3<br>';


    echo '<input type="checkbox" id="addfile4" onClick="uncheck(\'clearAll\');" name="fileck4" value="1">File 4<br>';


    echo '<input type="checkbox" id="addfile5" onClick="uncheck(\'clearAll\');" name="fileck5" value="1">Technical Drawing<p>';

    echo '<input type="checkbox" id="clearAll" onClick="uncheck(\'addfile1\',\'addfile2\',\'addfile3\',\'addfile4\',\'addfile5\');" name="clear" value="1" ><b>None of the above (clears above options)</b><br>';