I don't think I explained what I meant clearly.
I think John puts in the underscores because if He didn't all the code stuff could disappear when he posted it. He also puts in underscores when copy/pasting to notepad,whatever, because if he didn't the computer might act on the codes rather than transfer the whole text (including codes). You don't use the underscores on here when you actually want to do something,if you did then it wouldn't work because html wouldn't then recognise it as codes.