Tryit Editor v1.7

Source Code:

Result:

<!DOCTYPE html>
<html>
<head>
<script>
function printmsg()
{
alert("You are now about to print this document!");
}
</script>
</head>

<body onbeforeprint="printmsg()">

<h1>Try to print this document</h1>
<p><b>Tip:</b> Keyboard shortcuts, such as Ctrl+P sets the page to print.</p>
<p><b>Note:</b> The onbeforeprint attribute is only supported in Internet Explorer and Firefox. </p>

</body>
</html>

Edit the code above and click "Submit Code" to see the result.

W3Schools.com - Try it yourself

Source Code:	Result:
<!DOCTYPE html> <html> <head> <script> function printmsg() { alert("You are now about to print this document!"); } </script> </head> <body onbeforeprint="printmsg()"> <h1>Try to print this document</h1> <p><b>Tip:</b> Keyboard shortcuts, such as Ctrl+P sets the page to print.</p> <p><b>Note:</b> The onbeforeprint attribute is only supported in Internet Explorer and Firefox. </p> </body> </html>
Edit the code above and click "Submit Code" to see the result.	W3Schools.com - Try it yourself