title: Match regex that doesn't start with something
body: <p>I have seen a few other similar questions, but I can't seem to get it to work.  What I am trying to do is in JavaScript match a string with issue numbers.  I have that part working fine, but I don't want to match it if it starts with <code>target='_blank'&gt;</code>.</p>
  
  <p>These should match...  </p>
  
  <pre><code>Issue# 123  
  Issue #123  
  Issue 123  
  Issue no 123  
  Issue number 123  
  Issue: 123  
  </code></pre>
  
  <p>These should not...  </p>
  
  <pre><code>target='_blank'&gt;Issue# 123  
  target='_blank'&gt;Issue #123  
  target='_blank'&gt;Issue 123  
  target='_blank'&gt;Issue no 123  
  target='_blank'&gt;Issue number 123  
  target='_blank'&gt;Issue: 123
  </code></pre>
  
  <p>What I have so far is </p>
  
  <pre><code>(?!target='_blank'&gt;)(issue(?: number| no)?[ #:]?[ #]?([0-9]+))
  </code></pre>
  
  <p>But it is still matching the ones it shouldn't.</p>
  
  <p>Any help would be great.</p>