I have no clue what it is.

Well, XML is extensible markup language, text thst web pages are actually written in. The browser reads te text and puts words and pics together to 'look pretty' but it slows down opening a page. Gimme plain text and forget all the bullshit. If I want pics I'll ask.

Jar is a java archive. Java is an attempt to fuck up your computer by making it do things to 'enhance' your browser -- like downloading music or animation, but hiding it so you have to use special 'free' players that stick adverts in your face. Lemme save the mp3 or mp4 and play it when I want to!

The error is the web page author's fault -- and s/he expects you to fix it! Just like MicroCrap's Windows Scripting bull. Browsers should just ignore this shit and not allow openings for criminals to plant malware.

I'm aware this reads like a rant, but hackers should be summarily shot, not lauded. Bill Gates should be in jail for abetting all computer fraud. If he'd written Win correctly to begin with we wouldn't waste money on anti-virus cashsuckers.