I suspect this might easily be a clone question, it seems impossible that nobobdy would've asked this before, but my searches seem to return nothing.
I've grown very used to the MathJaX input here. So much, that when I need to show some maths to somebody, I'd go to Math.SE "Ask Question" and then just type it up there and then usually send it as a picture or something along those lines.
This is, however, very impractical (not to say lame)
My question therefore is: is there any way how to do this in a more sophisticated and practical way? Either output the Math.SE preview in a better way, or a (not necessarily) online editor. I've tried many different online editors, but they all fail at different details such as recognizing stars as bold/italic, characters such as $\mathbb{R}$ or $\mathscr{U}$, general formatting, etc.
Thanks!
Edit: I wouldn't want to turn this into a LaTeX online editor question. I am well aware of that and I can always give up and go to LaTeX. It's just that I love the input on Math.SE and would like to use it not just for asking questions here.
To demonstrate further - I sometimes take an existing answer on Math.SE and make edits on it (and/or translate it) for my own purposes. What would be the easiest way to do this?