Window.open navigates parent page to codeline url

Question

Guys I am using imagemap in c# where I am giving navigate ur to image map in code.I want new page to come up as popup which I have succeeded.but In mozilla My parent page changes url to :

"javascript:window.open('WebForm1.aspx','Graph','height=600,width=900');"

It works fine in chrome

My c# code for binding url to hotspots is like this:

RectangleHotSpot rh;
CoordBAL _cbl = new CoordBAL(SessionContext.SystemUser);

rh = new RectangleHotSpot();

rh.Top =  0;
rh.Bottom =500 ;
rh.Left = 0 ;
rh.Right = 500 ;
rh.NavigateUrl = "javascript:window.open('default.aspx','Graph','height=600,width=900');";

ImgMp.HotSpots.Add(rh);

Answer 1

I got the answer:

rh.NavigateUrl = "javascript:void(window.open('default.aspx','Graph','height=600,width=900'););";