How to create a label inside an <input> element?

Question

I would like to insert a descriptive text inside an input element that disappers when the user click on it.

I know it is a very common trick, but I do not know how to do

Answer 1

Here is a simple example, all it does is overlay an image (with whatever wording you want). I saw this technique somewhere. I am using the prototype library so you would need to modify if using something else. With the image loading after window.load it fails gracefully if javascript is disabled.