SQL database html textbox

I have html textbox and I want it to check by PHP and jQuery if the name of row in database already exist. For example I have table HELLO with ID and NAME. When user wrtie some name to textbox, I want the PHP开发者_开发问答 to check if the name already exist and jQuery to show user dynamic if it exist. How to do it?

Thx for help and let me know if u need more information.

1. Use jQuery to send an ajax request to php with the name typed in by the user.
2. Use PHP to check if the given name exists in the database and return a result as for example JSON.
3. Use jQuery to interpret the result and somehow show its findings to the user.