load times? how? are you saying that the code is so big that it lags to put it in a file and load it? if so why does things like jquery work fine? seems sus
if your code is over 15k lines im pretty sure a problem might exist, what on earth could take up 15k lines.
Also if it's only a few milliseconds, it would be easier to disperse it into scripts like "elements.js" just to make it like 1000% easier to add new code, instead of searching 15k lines