title: What compatibility do I lose when dropping the -khtml- vendor prefix?
body: <p>I have bits and pieces of CSS that use the <code>-webkit-</code> vendor prefix. For compatibility with "older" versions of Safari, I have the same rule with the <code>-khtml-</code> vendor prefix. I am actively uninterested in compatibility with Konqueror and other true KHTML browsers.</p>
  
  <p>For example, I may have the following rules:</p>
  
  <pre><code>.menuItem {
    -khtml-user-select: none;
    -webkit-user-select: none;
  }
  </code></pre>
  
  <p>I understand that modern WebKit browsers internally rewrite all <code>-khtml-</code> and <code>-apple-</code> rules to be <code>-webkit-</code> rules instead. However, that leaves me with the following question:</p>
  
  <p><strong>In what version of Safari did <code>-webkit-</code> become available? That is, what is the version before which Safari would completely ignore my rules?</strong></p>
  
  <p>I plan to use this information to find out whether my individual rules (such as <code>-khtml-user-select</code>) are actually supported by this early version of Safari.</p>