check input value after post

Question

I have test code

$chatText = "Hello world :D";

$chatText = str_replace(":D","<img src='happy.jpg' width='20' height='20' alt='Big Smile' />",$chatText);

echo $chatText;

basically what it does is replace the :D with an image. What I actually wanted to do is after clicking submit from a <textarea> -replace input value i.e emoticons (image) after post. How do I check user's input value to check to see if they have type these characters for example

":-)"

Answer 1

No need to check as str_replace will replace everything it matches, only check if the post isn't empty.

<?php
if($_POST['textarea_name']!=""){
    $text = $_POST['textarea_name'];
    $chatText = str_replace(":D","<img src='happy.jpg' width='20' height='20' alt='Big Smile' />",$text);
    echo $chatText;
}
?>

Check this out for more detailed replacement using arrays;

Emoticon Replacement - PHP