Restrict this regex to "edu", top-level domain

I have this regex that checks the validity of an email address

var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})开发者_开发技巧$/;

I want to tweak it so it ensures the email address entered is an .edu account.

PS - It's not for homework, I swear.

Change ([A-Za-z]{2,4}) into [Ee][Dd][Uu].

var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.[Ee][Dd][Uu]$/;

var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.(edu)$/i;