There's a nifty little button next to the "Create Thread"/"Reply" button. It says "Preview" on it.
Preview: A foretaste of something; An advance showing of a film, exhibition etc;
Something seen in advance; To show or watch something, or part of it,
before it is complete.
Never go through the embarrassment of having your steeze stink due to sneaky subversive scripting skulduggery ever again.