Validate username as the user types with jQuery and ASP.NET

Question

I want to validate a username as the user is typing according. The validation requirements are:

no whitespace;
no special characters;
within a defined minimum and maximum length; and
not the same as an existing username.

How do I do this using jQuery and ASP.NET?

barvo! I understood the question, may I ask what has been tried so far to achieve this — Satya, Jul 05 '13 at 09:47
yes, i have done this manually for points 1-It should not contain space, 3-It should have minimum & maximum length, 4-Is should not be duplicate / existing username — Nikhil Chavan, Jul 05 '13 at 09:47
@NikhilChavan see [this answer](http://stackoverflow.com/questions/13840143/jquery-check-if-special-characters-exists-in-string) for point 2. — James, Jul 05 '13 at 09:50

score 0 · Accepted Answer · answered Jul 05 '13 at 10:06

Try this:

$("input[type=textbox]").keydown(function(){
    if(/^[a-zA-Z0-9- ]*$/.test($(this).val()) == false) {
        alert('Your search string contains illegal characters.');
    }
    if(/\s/g.test($(this).val()) {
        alert("has white-space");
    }
    if(!$(this).val().length >= 8 && !$(this).val().length <= 25) {
        alert("out of range");
    }
});

For the fourth one you need to do it yourself because I don't have access to your field names etc.

Validate username as the user types with jQuery and ASP.NET

1 Answers1