Since I started writing this question, I think I figured out the answers to every question I had, but I thought I'd post anyway, as it might be useful to others and more clarification might be helpful.
I was trying to use a regular expression with lookahead with the javascript function split. For some reason it was not splitting the string even though it finds a match when I call match. I originally thought the problem was from using lookahead in my regular expression. Here is a simplified example:
Doesn't work:
"aaaaBaaaa".split("(?=B).");
Works:
"aaaaBaaaa".match("(?=B).");
It appears the problem was that in the split example, the passed string wasn't being interpreted as a regular expression. Using forward slashes instead of quotes seems to fix the problem.
"aaaaBaaaa".split(/(?=B)./);
I confirmed my theory with the following silly looking example:
"aaaaaaaa(?=B).aaaaaaa".split("(?=B).");
Does anyone else think it's strange that the match function assumes you have a regular expression while the split function does not?