<html><head><script src="https://libs.baidu.com/jquery/2.1.4/jquery.min.js"></script><script>$(document).ready(function(){ $("button").click(function(){ var txt = ""; txt += "Document width/height: " + $(document).width(); txt += "x" + $(document).height() + "\n"; txt += "Window width/height: " + $(window).width(); txt += "x" + $(window).height(); alert(txt); });});</script></head><body><button>Display dimensions of document and window</button></body></html>