window.open Not Working

Hi,

I was tring to open a HTML file using custom javaScript

I tried opening mailto link and it worked however not the html file

var mailto_link='mailto:omkar2001@gmail.com?subject=Test Mail&body=Body Content.....'
 win=window.open(mailto_link,'emailWin');
Works well.....

However

var mailto_link='test.html'
win=window.open(mailto_link,'emailWin');
Doesnot work.

Please suggest.