Tryit Editor v1.8

Source Code:
<!DOCTYPE html> <html> <head> <script src="../../ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"> </script> <script> $(document).ready(function(){ $(":checked").wrap("<span style='background-color:red' />"); }); </script> </head> <body> <form action=""> Name: <input type="text" name="user"><br> I have a bike: <input type="checkbox" name="vehicle" value="Bike"><br> I have a car: <input type="checkbox" name="vehicle" value="Car" checked="checked"><br> I have an airplane: <input type="checkbox" name="vehicle" value="Airplane"><br> <input type="submit"> </form> <p>Note: We use jQuerys .wrap method to highlight the selected elements, because Firefox does not support background color on checkboxes.</p> </body> </html>
Result:
W3Schools.com - Try it yourself