35
It depends on which language you're writing in (is this CSS, Javascript, HTML?)
For Javascript:
The standard Java commenting shortcuts are:
You can always find out shortcuts by hitting Ctrl-shift-l, which will bring up a list of all currently available shortcuts. They will change depending on if you have anything selected, what type of file you're editing, etc. Look for "Add comments", "Toggle block comments", "Toggle JS comments", and so forth.