title: check input value after post
body: <p>I have test code</p>
  
  <pre><code>$chatText = "Hello world :D";
  
  $chatText = str_replace(":D","&lt;img src='happy.jpg' width='20' height='20' alt='Big Smile' /&gt;",$chatText);
  
  echo $chatText;
  </code></pre>
  
  <p>basically what it does is replace the <code>:D</code> with an <code>image</code>. 
  What I actually wanted to do is after clicking submit from a <code>&lt;textarea&gt;</code> -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</p>
  
  <pre><code>":-)"
  </code></pre>