php - How to place two forms on the same page?

Question

I want to place both register and login form on the same page.
They both starts with:

if (!empty($_POST)) ... 

so, I need something like:

if (!empty($_POST_01))...  // regForm
  and 
if (!empty($_POST_02))...  //loginForm

Also how to prevent executing first form if the second is busy, and vice versa (user clicks on both)
My idea is to create a simple variable on starting process, for example $x = 1 and at the end of process $x = 0, so:

if ((!empty($_POST_01)) And $x = 0)...

Probably, there is a better way.

Answer 1

You could make two forms with 2 different actions

<form action="login.php" method="post">
    <input type="text" name="user">
    <input type="password" name="password">
    <input type="submit" value="Login">
</form>

<br />

<form action="register.php" method="post">
    <input type="text" name="user">
    <input type="password" name="password">
    <input type="submit" value="Register">
</form>

Or do this

<form action="doStuff.php" method="post">
    <input type="text" name="user">
    <input type="password" name="password">
    <input type="hidden" name="action" value="login">
    <input type="submit" value="Login">
</form>

<br />

<form action="doStuff.php" method="post">
    <input type="text" name="user">
    <input type="password" name="password">
    <input type="hidden" name="action" value="register">
    <input type="submit" value="Register">
</form>

Then you PHP file would work as a switch($_POST['action']) ... furthermore, they can't click on both links at the same time or make a simultaneous request, each submit is a separate request.

Your PHP would then go on with the switch logic or have different php files doing a login procedure then a registration procedure