Show various widths. Note the values are from the iframe so might be smaller than you expected. The yellow highlight shows the iframe body.

Edit code and click me	Your Result (Some examples do not work in Google Chrome):
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <style> body { background:yellow; } button { font-size:12px; margin:2px; } p { width:150px; border:1px red solid; } div { color:red; font-weight:bold; } </style> <script src="/scripts/jquery-1.4.js"></script> <script> $(document).ready(function(){ function showWidth(ele, w) { $("div").text("The width for the " + ele + " is " + w + "px."); } $("#getp").click(function () { showWidth("paragraph", $("p").width()); }); $("#getd").click(function () { showWidth("document", $(document).width()); }); $("#getw").click(function () { showWidth("window", $(window).width()); }); }); </script> </head> <body> <button id="getp">Get Paragraph Width</button> <button id="getd">Get Document Width</button> <button id="getw">Get Window Width</button> <div> </div> <p> Sample paragraph to test width </p> </body> </html>
Edit the code above and click to see the result	www.xhtml.co.il - Try it yourself