Finds the button with no siblings in each matched div and modifies look.

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> <script src="http://code.jquery.com/jquery-latest.js"></script> <script> $(document).ready(function(){ $("div button:only-child").text("Alone").css("border", "2px blue solid"); }); </script> <style> div { width:100px; height:80px; margin:5px; float:left; background:#b9e } </style> </head> <body> <div> <button>Sibling!</button> <button>Sibling!</button> </div> <div> <button>Sibling!</button> </div> <div> None </div> <div> <button>Sibling!</button> <button>Sibling!</button> <button>Sibling!</button> </div> <div> <button>Sibling!</button> </div> </body> </html>
Edit the code above and click to see the result	www.xhtml.co.il - Try it yourself