opening page in a new window

i have a menu script whcih displays menu on mouse over

it works fine

only thing i want to know is how do i open any particular page in a new window& pass paramters

ealier i was having a href instead of menu so had used target=_blank

currently when the menu option is clicked the new page opens in same window & no parameters are passed

here is the menu option

  mm_menu_0113121624_0.addMenuItem("Employee details", "location='EMPDETAILS.aspx?type=E'");

i need to open EMPDETAILS.aspx in  anew window & also pass parametr