Safari: SyntaxError - Parse error

I have now worked my way past this particularly opaque Safari error message twice, which is one time too many, so I am putting the explanation for my error case online. Safari seems to have a few cases where it throws up this utterly useless error message. It does include a line number reference, and double-clicking the error line in the log will take you to the offending line, but heaven help you if it is not clear what is wrong at that point.

I found another reference to this problem on the web, but it wasn’t the problem I had.

My problem was that I used “abstract” as a variable name. Because I am working on web pages for viewing presentation abstracts, this seemed natural, however I guess “abstract” is a reserved word of some kind in Safari’s Javascript implementation. Firefox showed no errors and happily ran code that Safari could not even parse.