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

Please use PlaceHolder.JS its works in all browsers and very easy for non html5 compliant browsers http://jamesallardice.github.io/Placeholders.js/