单击“提交”时验证textarea

Question

I am developing website that allow user sending feedback to system. I have created feedback form by using textarea and button for submit. In most important thing is when user click on submit, if user input some words that I don't want them to input, that feedback won't send to the system; it will alert user to drop out that word before cicking submit.

Since now, i just create a simple code that will echo some warning if user input the word that i don't want them to input in feedback form.

Here is my code

<form action="main.php" method="post">
    <textarea cols='10' rows='5' name='text'></textarea>
    <br/>
    <input type='submit' name='add' Value='Add to list' />
</form>

<?php
if (isset($_POST['add'])) {
    $banned = array('dog', 'cat', 'cow'); // Add more
    $entry = $_POST['add'];
    foreach($banned as $word): if (strpos($entry, $word) !== false) die('Contains banned word');
    endforeach;
}
?> 

It is not work. Can anyone help me to solve this problem?

Thank in advance.

Answer 1

Try like

$entry = $_POST['text'];    // Not $_POST['add'];
foreach ($banned as $word):
    if (strpos($entry, $word) !== false) {
        echo 'Contains banned word';
        exit;
    }
endforeach;

Your $entry will be the text box value i.e. $_POST['text'] not $_POST['add']