qs

<?php
if($_SERVER['REQUEST_METHOD'] === 'POST'):
    // Receive the input
    $input = trim($_POST['input'], ', '); // remove any extra commas and spaces
    $arr1 = explode(', ', $input); // separated by comma and space
    $frq = array_count_values($arr1); // This function returns an array of keys and values. the keys are the original array values and the values are the frequency of elements
    arsort($frq); // arrange it from bigger to lower (most frequent to less)

    // Get the array of the keys [The words]
    $frq = array_keys($frq);

    // Now show the result
    $arranged = "";
    foreach($frq as $element){
        $arranged .= $element . " -> ";
    }
    $arranged = rtrim($arranged, '-> '); // remove the last "-> "
    echo "The words you entered from most frequent to less frequent are : " . $arranged;
else:
?>
    <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="POST">
        <input type="text" name="input" />
        <input type='submit' />
    </form>
<?php endif; ?>