>This may not be ideal (opens a new window & closes it, if required window not already open), but it may do what you require - basically try opening a window with the required name & check the contents of that window, if blank close the window, otherwise load your URL :-
>
>

>var TargetWin = null ;
>TargetWin = window.open( '', 'MyName', 'left=2000' )
>if ( TargetWin.document.location == 'about:blank' )
> {
> TargetWin.close() ;
> TargetWin = null ;
> }
>else
> {
> TargetWin.navigate( 'YourURL' )
> }
>

>
>You may need to alter the 3rd parameter of the open method to ensure that the empty window is opened off screen to avoid the window flashing on & off.

Ok, thanks for the info, within that situation, I'll rethink about this entire challenge.