IE throws Invalid Argument when calling window.open() ??

In my javascript code, I try to open a new window to hold a div ( a block of contents ) for printing.  And IE throws me an "Invalid Argument" error ( while other browsers are fine, which is usually the case ~ ).

I search online, there are 2 different methods to deal with this problem:

1)   var w = (window.open(urlstring, wname, wfeatures, false));

2) You cannot have 'space' in between "wname" items in IE.

I tried the first one, it doesn't work; and I tried the second 
one, and it works.

For the method one and its explanation, here is the link
http://stackoverflow.com/questions/710756/ie8-var-w-window-open-message-invalid-argument