show and hide buttons or link while printout page

javascript funtion
function ShowHelp(id) {
document.getElementById(id).style.display = "block";
}
function HideHelp(id) {
document.getElementById(id).style.display = "none";
window.print();
setTimeout("ShowHelp('aprint')", 3000);


}
function HideHelp1(id) {
document.getElementById(id).style.display = "none";

setTimeout("ShowHelp('imgbtdelorder')", 3000);


}


calling on button click

a id="aprint" onclick="javascript:HideHelp1('imgbtdelorder');javascript:HideHelp('aprint');" href="JavaScript:window.print();">Print this page a