User Registration page about the problem for guidance

User Registration page Problem ask for directions AH
I used PHP AJAX to write a user registration page if the user name does not pass, you can not jump to the next line to enter the password how to do?
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Code? Code?
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Suddenly find out that you're useful for jquery


So what are you going to do with your own writing?
I suggest you rewrite it as a straightforward example of jquery.

The digits are not available and the letters begin with

User name:
3-16 characters

check.php

 
 echo is_numeric ($_post[' username ']{0})? 1:0;

Isn't it simple?

