Test in Firefox 2 and IE 7.It work smooth.

The animation needs to run when the user moves their mouse over and out of the navigation. The key thing to note is that any animation is stopped before attempting to animate again. This avoids animations queuing up from repeatedly moving the mouse in and out of the element.

A jQuery plugin to specify examples within form inputs (i.e. text fields and text areas) that disappear on user focus. by Paul Mucur

Sometimes you often need to find a way to focus a user on a current context. Here is a nice way of achieving this effect.