Question

When I click y link,it is going to x.Why is that ?

<a href="test.php?hello=x">x</a>
    <a href="test.php?hello=y">y</a>
    <?php
    if(isset($_REQUEST['hello']) == 'x')
    {
    echo 'x';
    }
    else if(isset($_REQUEST['hello']) == 'y'){
    echo 'y';
    }
    else
    {
    echo "else";
    }

Answer 1

The isset function returns either true or false and you are comparing that return value with strings 'x' and 'y'.

Since you are using == and not ===, true == 'x' will return ture.

To fix this first you need to check if the variable is set and only then compare it.

if(isset($_REQUEST['hello']) && ($_REQUEST['hello']) === 'x'))