كود يجعل الصفحة تهتز لفترة قصيرة عن الدخول عليها

<script language="JavaScript">
<!---
bName = navigator.appName;
bVer = parseInt(navigator.appVersion);
if (bName == "Netscape" && bVer == 3) ver = "n3";
else if (bName == "Netscape" && bVer == 2) ver = "n2";
else if (bName == "Netscape" && bVer >= 4) ver = "n4";
else if (bName == "Microsoft Internet Explorer" && bVer == 2) ver = "e3";
else if (bName == "Microsoft Internet Explorer" && bVer > 2) ver = "e4";

if (navigator.appVersion.indexOf("Mac") != -1) ver+="m";
function shake() {
if (ver == "n4" || ver == "n4m" || ver == "e4" || ver == "e4m") {
for (i = 10; i > 0; i--) {
for (z = 4; z > 0; z--) {
self.moveBy(0,i);
self.moveBy(i,0);
self.moveBy(0,-i);
self.moveBy(-i,0);
} }
}
}
setTimeout('shake()',5000);
// --->
</script>