<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 += "Width of div: " + $("#div1").width() + "</br>"; txt += "Height of div: " + $("#div1").height(); $("#div1").html(txt); });});</script><style>#div1 { height: 100px; width: 300px; padding: 10px; margin: 3px; border: 1px solid blue; background-color: lightblue;}</style></head><body><div id="div1"></div><br><button>Display dimensions of div</button><p>width() - returns the width of an element.</p><p>height() - returns the height of an element.</p></body></html>