title: PHP: How to split a string at keyword
body: <p>I am trying to split a string at keyword <em><code>"http://"</code></em>.</p>
  
  <pre><code>explode("http://", $input);
  </code></pre>
  
  <p>This doesn't work for me because it does not only split the <code>$input</code> but it also deletes <em><code>"http://"</code></em> from the string, which i don't want to happen.</p>
  
  <p>What is the most effecient and fast way of doing this ? 
  I didn't find any function for this so far.</p>