title: Javascript: Check if this window is already opened
body: <p>I am trying to detect whether the current page is already opened in a different tab or not.</p>
  
  <p>I tried using window.open(), but I get as return the current window itself, not the supposedly other window of same address. It will always return true.</p>
  
  <p>So say, if 'mysite.com' is already opened, when the user opens a new window with 'mysite.com', I shall detect that, focus the other window and close the current one.</p>
  
  <p>Would love to hear any ideas, or whether this is possible. I'm trying to capture all links into a single tab.</p>