function OpenPopUp(MyFile,MyWindow,MyWidth,MyHeight){	  
	var ns4 = (document.layers)? true:false; 	  //NS 4
	var ie4 = (document.all)? true:false;	  //IE 4
	var dom = (document.getElementById)? true:false;	  //DOM
	var xMax, yMax, xOffset, yOffset;;	  
    	if (ie4 || dom){
        	xMax = screen.width;
        	yMax = screen.height;
        }
    else if (ns4){
        xMax = window.outerWidth;
        yMax = window.outerHeight;
    }
    else{
        xMax = 800;
        yMax = 600;
    }
    xOffset = (xMax - MyWidth)/2;
    yOffset = (yMax - MyHeight)/2;
    window.open(MyFile,MyWindow,'width='+MyWidth
	+',height='+MyHeight
	+',screenX='+xOffset
	+',screenY='+yOffset
	+',top='+yOffset
	+',left='+xOffset
	+',status=no,location=yes,toolbar=no,directories=no,resizable=no,scrollbars=yes,status=yes,location=no');
}