10.4 - How do I check to see if a child window is open, before opening another?

  var myWin;
  function openWin(aURL) {
    if (!myWin || myWin.closed ) {
      myWin = window.open(aURL,'myWin');
    } else {
      myWin.location.href = aURL;
      myWin.focus();
    }
  }

Popup windows cause usability problems and are generally best avoided.

• https://developer.mozilla.org/en/DOM:window.open
• http://msdn.microsoft.com/en-us/library/ms533574%28VS.85%29.aspx
• http://docs.sun.com/source/816-6408-10/window.htm#1201877
• http://www.useit.com/alertbox/990530.html