php, form using the same page after submittion

Question

I'm wondering what's the easiest way to make let's say a form with user/pass and submit button with php but after you submit it goes back to the same page instead of going to another php page.

I'm thinking of if/else statement but a bit confused how to set it after lots tries but still not getting the result wanted

weird I did all those you guys said before I posted..but...>.<" let's say just something simple like this...

but I also want to set if nothing is entered then sumbit is clicked there'll be an error....should be something easy but I don't know why I can't seem to figure it out

<?php
function userPass()
{
    echo "<form method='post' action=" . $_SERVER['PHP_SELF'] . ">";
    echo "<input type='text' name='user' /><br/>";
    echo "<input type='text' name='pass' /><br/>";
    echo "<input type='submit' value='Login' />";
}
    if(empty($_POST["user"]))
    {
        userPass();
    }
    if(!(empty($_POST["user"])))
    {
        if($_POST["user"] == "comp")
        {
            echo "Welcome comp";
        }
        else
        {
            echo "Wrong user";
        }
    }
    ?>

Answer 1

Just use below syntax

<form method="post" action="">

You can check whether post is set using isset() method.

Answer 2

this code will help you

<form action="<?= $_SERVER['REQUEST_URI'] ?>" method="post">

or you could just do this:

<form action="" method="post">

Thank you ....