[jQuery] Form validation - Add "http://" to text field if user forgot it

[jQuery] Form validation - Add "http://" to text field if user forgot it


In my form I have a couple of text fields into which the user enters
links.
<input type="text" name="link1" id="link1" />
<input type="text" name="link2" id="link2" />
<input type="text" name="link3" id="link3" />
Now I want to create a function that runs after the user has entered a
link. It should automatically add "http://" in the beginning of the
link if the user forgot it. How do I do that?