Why do we need javascript

Edward Colins · September 18th, 2010, 03:02 PM

i have tried the try it out for validation using custom validator.
i ran the code and it worked even when i didn't put the javascript code, and the red asterisk appeared when other red asterisks appeared too, means it appeared on the client side..

Imar · September 19th, 2010, 06:56 AM

Hi there,

Take a look at page 300, under the heading "A Warning on Client-Side Validation". The JavaScript executes at the client, giving users immediate feedback without the need for a postback.

Cheers,

Imar

Edward Colins · September 19th, 2010, 11:23 AM

hello, i tried the javascript as mentioned in the book , and it renders in the browser without errors, but when i fill any on the phone numbers text boxes, the red start (*) is not removed immediately unless i post back the page to the server which means that the java script is not working on the page.
here is my code :

Code:

<script type="text/javascript">
    function ValidatePhoneNumbers(source, args) {
        var phoneHome = document.getElementById('<%= PhoneHome.ClientID %>');
        var phoneBusiness = document.getElementById('<%= PhoneBusiness.ClientID %>');
        if (phoneHome.value != '' || phoneBusiness.value != '') {
            args.IsValid = true;
        }
        else {
            args.IsValid = false;
        }
    }

and for the custom validation, i made the client validation function property = ValidatePhoneNumbers, should i change the control to validate?

Imar · September 19th, 2010, 12:45 PM

Hi there,

This is by design. Since the control is not directly associated with an HTML form control (it uses multiple controls in the validation function), validation is carried out when you click a submit button.

Cheers,

Imar

Edward Colins · September 19th, 2010, 12:52 PM

so when i put the javascript and when i removed it, it has the same behavior, both cases i need to post back again to get rid of the red star? why do i need it !!!!

Imar · September 19th, 2010, 01:06 PM

You don't *need* it, but as I explained in the book, it serves as a courtesy to the user so they don't have to postback, but get an immediate respons.

If you're seeing a postback when you leave both fields empty and click the button, something is wrong. Can you check if it really posts back (you should see the browser's progress bar) and if it does, post the full code for the entire control?

Cheers,

Imar

Edward Colins · September 19th, 2010, 01:49 PM

ahaa, thanks , i thought the star will disappear as soon as i fill data in the text box without clicking the button :) thanks :)

Imar · September 19th, 2010, 02:50 PM

Not with this CustomValidator. It does work for the other validators in the page, such as the RequiredFieldValidator.

Cheers,

Imar