jQuery 1.4.4, HTML, CSS, JavaScript
jQuery 2.1.3, HTML, CSS, JavaScript
Mootools 1.3 (compat), HTML, CSS, JavaScript
A lot of people thing 'preventDefault()' is the same as just returning false from something like a link click. It's not. Depending on the application you may see no difference but it does make a difference if the event is bubbled upwards.