<!DOCTYPE html>
<html>
<head>
<title>html tutorial - html5 - html code - html form - In 30Sec by Microsoft Award MVP - | wikitechy HTML onbeforeunload Attribute</title>
</head>
<body onbeforeunload="return onBeforeUnload()">
<a href="http://www.wikitechy.com/">Click here to go to Wikitechy.com</a>
<script>
function onBeforeUnload() {
return "Write something here...";
}
</script>
</body>
</html>
<html>
<head>
<title>html tutorial - html5 - html code - html form - In 30Sec by Microsoft Award MVP - | wikitechy HTML onbeforeunload Attribute</title>
</head>
<body onbeforeunload="return onBeforeUnload()">
<a href="http://www.wikitechy.com/">Click here to go to Wikitechy.com</a>
<script>
function onBeforeUnload() {
return "Write something here...";
}
</script>
</body>
</html>
Result