shown=''
function OpenFile(url) {
if( shown=='' || shown.closed) {
        shown=window.open(url,'OpenFile','scrollbars=no,status=no, high,width=400,height=300');
}
else{ 
        shown.close();
        shown=window.open(url,'OpenFile','scrollbars=no,status=no, high,width=400,height=300');
}
}