code for check availability

Repected sir:

Needed code for
"Automatic check should be applicable for the
Registration form like "CHECK AVAILABILITY" feature"
i.e;
example
"vijay.kk@code.com" "CHECK AVAILABILITY"

Now when the CHECK AVAILABILITY
is clicked,
it should show error if this login name already exists
else it should show as

"[email protected]"
"[email protected]"
"[email protected]"

Repected sir:

Needed code for
"Automatic check should be applicable for the
Registration form like "CHECK AVAILABILITY" feature"
i.e;
example
"[email protected]" "CHECK AVAILABILITY"

Now when the CHECK AVAILABILITY
is clicked,
it should show error if this login name already exists
else it should show as

"[email protected]"
"[email protected]"
"[email protected]"

You will have just to create a javascript function that using ajax to call for example a php page which do a select query to database to search for the specific email , it exists so return message " already exists" if not "Not exists"
Example using AJAX:

ajax/ajax-sending-a-request-to-a-server-t5684.html
ajax/login-using-ajax-t3234.html
jquery-examples/load-file-and-update-content-using-ajax-and-jquery-t10685.html