javascript，获取选择框中所有值的列表

I am stumped. I have a form with a dropdown list, and I would like to grab a list of all the values in the list. I pulled the below example from w3 schools (yes, I know it's unreliable, but other solutions on stack overflow seem to be very similar to this). It was not working for me, and I tried plugging it into jsfiddle, but no luck.I am stumped. I have a form with a dropdown lis