Question

i have an app and when i write a number in a textbox,i have to check if this number exists in database or not.How can i do that with Custom Validator and JQuery Ajax functions ? Thank you so much in advance

Answer 1

You can not write a JavaScript to connect to SQL.

1. write a function in your js to ajax post your textbox value to a server side validation method.
2. Serverside validation method check given value with your database
   and return true or false.
3. validation function in your js reflect properly with your ajax post
   results on success.

References to study:
1. api.jquery.com: look for $.post