try this one:
showModalDialog(
v_location,
'',
'dialogHeight:260px; dialogWidth:560px; edge: Raised; center: Yes; help: No; resizable: Yes; status: Yes; scroll: Yes');
That will give you window which can be resized by user/visitor. And yes it is possible to dynamically change size of the windows based for example on screen resolution, you will need to replace 'dialogHeight:260px; dialogWidth:560px;...' with something like 'dialogHeight:<%=WindowsHeight%>px; dialogWidth:<%=WindowWidth%>px;...' Specifics will depend on what your needs are.