I'm hacking up Nav Bar II found at dynamicdrive.com

I need to absolutely position it on the page, okay easy enough. But the problem is the netscape absolute position is about 6 pixels south of the IE absolute position. I need those 2 to be equal. There is a function built into the script to move the bar, but I need this movement based on whether they are using NS or IE. So I need it moved if the user is using NS and I need nothing to happen if they're not.

Unfortunately I'm not a big javascript jockey so after trying for a bit I could use some help.

Code:
function init() {

  // Get width of window, need to account for scrollbar width in Netscape.

  fullWidth = getWindowWidth() 
    - (isMinNS4 && getWindowHeight() < getPageHeight() ? 16 : 0);

  myNavBar1.resize(340);
  myNavBar1.create();
  myNavBar1.setzIndex(2);
  myNavBar1.moveTo(190, 160);	
  myNavBar1.moveBy(0, -6);
}
Now what I need is the display of that last line, mynavbar1.moveby(0, -6), dependent on what browser the user is using.

Chris