<html><body><p>The addEventListener() method is not supported Internet Explorer 8 and earlier versions.</p><p>This example demonstrates a solution that will work for all browsers.</p><button id="myBtn">Try it</button><script>var x = document.getElementById("myBtn");if (x.addEventListener) { x.addEventListener("click", myFunction);} else if (x.attachEvent) { x.attachEvent("onclick", myFunction);}function myFunction() { alert("Hello World!");}</script></body></html>