php login with forms

[mycro]

How would I make a form that will only submit if the username and password fields are correct? the form has username, password, and some other fields to submit information. I remember seeing a small tutorial on this but i cant remember where i saw it. It is like this:

Username:
Password:

Comment to submit:

Submit

All on the same page. I think it would be best to somehow include a seperate file with the login and password. Please help, thanks.

[sarahk]

make the submit button actually a regular button which calls a javascript (linked file) and if that works out then the javascript calls document.formname.submit();

However this is so insecure that it's not worth the effort.

If there's a block which prevents you altering the script you are posting to then I would recommend posting to your own validation script printing out into a confirmation form (html and hidden fields) with an "ok to proceed" button. This confirmation form then calls the script you really want to post to.