Back in 1999, the browser would pop up a window for every error. Sometimes the first error would trigger more errors down the line and I'd have a whole series of windows popping up while my stress levels elevated. At least those pop ups don't happen anymore.
The point to remember about multiple errors is to always start fixing at the beginning. That first error probably created the other errors. Chances are that I may not have as many errors as I thought. JavaScript is a very logical language that likes to work in a linear fashion. By fixing that first mistake, I may fix the subsequent errors which depended on the first mistake to work properly!
I just have to figure out how better to use the Developer Tools of each browser (like I don't have enough to learn!)
If an error reports something is "undefined," this is a runtime error and usually means a line was broken into two, or there is a typo. Try removing (or commenting out) a line and see if the script works without it.
With the knowledge acquired so far regarding errors, about 99% of scripting mistakes can be fixed without even using some debugging software!
