Just kidding :)
If your intent is to have her get the hang of programming, javascript probably isn't the best language. There's a lot of overhead involved in running a simple program such as
Enter your name:
> Alice
Hi, Alice!
Enter your age:
> 20
Alice, your age minus 10 is 10!
As I'm sure you know, javascript is used to manipulate the DOM and process data entered by the user in forms. Any sane person will tell you to just use jQuery -- plain javascript requires a lot of boiler-plate non-business-logic code to replicate the above example. At that point you're just learning jQuery, which is useful knowledge, but very domain specific.I started with BASIC but obviously today I would recommend Python. Python has a REPL like javascript with Chrome or Firefox with Firebug, but unlike javascript you can easily write up some code and run it in the command line. A really important benefit of Python is that the interpreter will give you good debugging information (not properly indented, variable not initialized) whereas IMO javascript doesn't have such great error messages.
That said, if you still wish to have her learn javascript, http://www.w3schools.com/js/default.asp is probably the best site. It's where I learned.