From my experience, IntelliJ is the quickest way to get started.
If you already use eclipse regularly and are comfortable with it, you could try it, but intelliJ works as soon as you install the scala plugin.
I agree with your professor. Once you have a few source files an IDE really helps. But learning any IDE requires effort so allow a bit of time to ...
Sorry,I got answer by myself.
I should specify the document which IE ver use in html file.
＜meta http-equiv="x-ua-compatible" content="IE=10" ＞
index2.html is changed as fallows
<meta http-equiv="x-ua-compatible" ...