HELP - How to clear the URL PAR

I built a user registration system for my eCart.

However I have a small issue.

I am using a simple show if which allows me to show an error message if the username is already taken.


<?php if(isset($_GET['BadUserName']) && $_GET['BadUserName'] == "1") { ?>
<div id="RegFailDIV">UserName is Taken. Please Try Another.</div>
<div id="LoginFailDIV"></div>
<?php } ?>

The issue is cause by the fact that my form can fail for multiple reasons. For example captcha is wrong.

The issue arises when the username box displays, if a user re types the form with a available username, submits the form, if the form fails for a different reason, and returns to the page, the username box still appears, because the URL par has not been removed.

Could you tell me how to clear the URL PAR when the form is re-submitted.

Also,

I need to make my passwords encrypted.

Although I know how to do this and make it work with my login and registration pages. I do not know how to make email password work. This is because the email password would email the encrypted password in its default state.

Could you tell me how to do this.


Thank you.