Need an ajax hack that will disable the word Internet in "Where did you find us"field
 

Ok so apparently making the description bold and saying "Do not put internet" where you found us isn't enough for some of the bright people on the internet.

I need a hack that when someone types in internet or "the internet" in the Where did you find us field it will turn red and maybe pop up with a funny custom message that I put in.

Anyone game for it?

This is on the Registration page btw

I don't see where AJAX comes into the story?

Just like the username one. When they enter Internet I want it to automatically tell them not to do so and not let them proceed. Not just when they try to submit it

it can be done with Javascript. AJAX is only for sending/recieving data through streams.
you could have a function on the submit button: onsubmit="checknet"
then in javascript you would have the function:
function checknet(){
formbitvalue = document.theformname.theformfieldname.value;
if (formbitvalue=='Internet'){
alert "Bleugh !!!";
}
}