title: How to detect if browser supports "plaintext-only" value in contenteditable parameter?
body: <p>I can't find any relevant information about "contenteditable" HTML5 parameter. I've found out, that Google Plus is using this for Chrome browsers:</p>
  
  <pre><code>&lt;div contenteditable="plaintext-only"&gt;&lt;/div&gt;
  </code></pre>
  
  <p>It seems that no other browsers support this and it's only Chrome proprietary value. I want to use it in my project. However, I need to detect the browser and find out if supports "plaintext-only" setting.</p>
  
  <p>Of course, I could detect only Chrome, but there might be other browsers that support it (I don't know about any at this moment) or other main stream browsers might start supporting this feature in future. </p>
  
  <p>So I would rather detect if the "plaintext-only" functionality is supported than detecting just Chrome browser.</p>
  
  <p>Anyone can help me on this ?</p>