How to call a function after textbox lose focus
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I have no experience with Javascript/JQuery/AJAX so I'm trying to understand if it's possible to call a function that execute a query on my DB after a textbox lose focus.

I'm displaying a table in my page (using PHP) with text boxes that contains the same values of a table on my DB, and when someone change the value on a text box I want to change the DB table with an UPDATE query to make them equals; is that a way with AJAX or JQuery to do this? 

Thanks in advantage