Calling PHP from JavaScript validation

tomgone

Hiya,

I'm using a little JavaScript to validate a form (so I can validate each field rather than sending the whole form back and forth). This is a registration form so what I would like to do, is to be able to call a php script after the user has chosen a username. The php script then connects to a MySQL db, checks if the username exists, and then "informs" the main page of the result. If there is an error, the user needs to pick a new username and so on.

So basically, from the website on screen, call a PHP script that connects to a MySQL db, returns a results to the original page and then carries on from there.

Phew, any ideas anyone?

Best regards
Thomas

Anon

Once the page has loaded, PHP is finished working so you wouldn't be able to do anything "dynamic" like that.

Your options would be to populate an array of all your users on load and have JavaScript check it for a match (suggestion : convert the array and the desired username to all uppercase letters so that Greg and greg don't both join)

========== OR =============

ON the submit of the form, have a "validate.php3" page that checks all your required information and if it is okay, allow the user to be joined. IF there is an error, give them the problem message and send them back to correct the error.

tomgone

I didnt really want to send all info back, validate it with PHP, and then reload a potential page with all error highlighted. Rather, as I am doing now, I'd rather find each error as they "occurr" so to say. So what I was looking for was a way to call a PHP script back on the server from the JavaScript, which waited for a message and then deal with it. Something like;

function validation() {
if(phpscript(username) == false) {
alert("Your username exists");
}

and where phpscript.php would then do the checking with a MySQL db etc.

If this is not possible, I'll have to do the checking via a php script which is called from the form action.

Cheers for your time
Thomas

Anon

I don't think it is possible since PHP is all server-parsed and has no impact on the page once it is loaded.

tomgone

My thoughts were along the line of letting the JavaScript call a page. This page would be a PHP file which would be parsed on the server. During this parse it would check if the username exists, and if so, the returned page would have some flag set. The JavaScript would pick up that flag, close the PHP reply page and carry on where it was.

The alternative I have is otherwise to validate all other things, and then send the page of, and the only thing I need to check is for a duplicate username, and could have a requester/alert popup asking for a replacement username.

Still always fun trying the "hard" way.

Cheers
Thomas