Okay, I found it. (It was hiding in a sub-dialog.)
Navigate to chrome://settings (or menu > “Settings”)
Under “Privacy” click the “Content settings…” button.
In the “Content settings” dialog:
Under the “JavaScript” section, either:
a) choose "Allow all sites to run JavaScript (recommended)"
or
b) select the “Do not allow…” choice, but add my.sketchup.com in the “Manage exceptions” sub-dialog.
You may need to do the same down in the ‘Pop-ups’ section as my.sketchup.com is likely to use some popup windows for the UI.
JavaScript isn’t disabled, and I’m on the latest version of Chrome. Too much on my plate @ the moment to worry about troubleshooting this. Last thing I want to do is break Chrome (my main working Browser). As a teacher, I was mainly curious to see how my.sketchup.com worked. Since many schools are moving away from computers with a full O/S (such as Chromebooks), a web based version of SketchUp would be useful. Has anyone tested on a Chromebook or even an tablet/iPad for that matter?