title: PHP Find String inside Text
body: <p>What is the best/easiest way to find a string (with PHP) inside a text with:</p>
  
  <ul>
  <li>Any kind of special characters</li>
  <li>String boundary (space)</li>
  <li>Case insensitive  </li>
  </ul>
  
  <p>Some examples:</p>
  
  <pre><code>$text = "This is a test èsàdò string123?"; 
  $find = "èsàDò"; 
  </code></pre>
  
  <p>Will return <code>true</code> </p>
  
  <pre><code>$text = "This is a test èsàdò string123?"; 
  $find = "a TEST èsàdò";
  </code></pre>
  
  <p>Will return <code>true</code> </p>
  
  <pre><code>$text = "This is a test èsàdò string123?";
  $find = "string123";
  </code></pre>
  
  <p>Will return <code>true</code></p>
  
  <pre><code>$text = "This is a test èsàdò string123?";
  $find = "string12";
  </code></pre>
  
  <p>Will return <code>false</code></p>
  
  <pre><code>$text = "This is a test èsàdò string123?";
  $find = "This is a test èsàdò String123?";
  </code></pre>
  
  <p>Will return <code>true</code></p>