title: Possible options/bugs that may cause Internet Explorer to spawn multiple tabs?
body: <p>From an HTML/JavaScript perspective I'm currently aware of 2 methods to spawn a new browser tab (or window).</p>
  
  <ol>
  <li>An HTML form <code>&lt;form&gt;</code> or anchor <code>&lt;a&gt;</code> with a target attribute e.g. <code>target="_blank"</code></li>
  <li>A JavaScript call to <code>window.open(url, name, features);</code></li>
  </ol>
  
  <p><strong>Note:</strong> I'm intentionally ignoring the IE-only <a href="https://msdn.microsoft.com/en-ca/library/ie/ms536759%28v=vs.85%29.aspx" rel="nofollow">showModalDialog</a> &amp; <a href="https://msdn.microsoft.com/en-ca/library/ie/ms536761%28v=vs.85%29.aspx" rel="nofollow">showModelessDialog</a> methods.</p>
  
  <p>However I recently encountered a very buggy scenario where I was able to spawn multiple tabs (<em>actually endless</em>) without clicking a link, submitting a form, or calling window.open() in Internet Explorer ONLY just by loading a page.</p>
  
  <p>Since this bug was causing a terrible user experience (<em>essentially browser lockup</em>) I quickly mitigated the issue by blocking direct access to this screen - but I'm baffled as to how the other tabs could even spawn (regardless of the actual bug) if none of the options mentioned above were triggered.</p>
  
  <p>Sadly the screen in question involves some SSO/security related login code so I can't post the details here but I'd love to know if there are any other ways to spawn new tabs that I might have overlooked so that I can dig into the code to see if there is a resolution.</p>
  
  <p>e.g. Are there any HTTP Headers that might trigger a new tab?</p>