function MM_openBrWindow(theURL,winName,features) { //v2.0
  var wOpen = window.open(theURL,winName,features);
  
  if (!wOpen.closed) {
    wOpen.focus();
  }
}

function MM_openBrWindowCentred(theURL,winName, w, h) {
    if (document.all)
        var xMax = screen.width, yMax = screen.height;
    else
        if (document.layers)
            var xMax = window.outerWidth, yMax = window.outerHeight;
        else
            var xMax = 640, yMax=480;

    var xOffset = (xMax - w)/2, yOffset = (yMax - h)/2;

    var wOpen = window.open(theURL,winName,'width='+w+',height='+h+',screenX='+xOffset+',screenY='+yOffset+',top='+yOffset+',left='+xOffset+'');
    
    if (!wOpen.closed) {
      wOpen.focus();
    }
}