Randomly generate either -1 or 1

I was coding something and wanted to generate either -1 or 1, and nothing else. I was trying to find a quick way to do it, and I think this is the best way (example is in JavaScript):

var foo = 1 - 2 * Math.round(Math.random());

While this example is in JavaScript, it shouldn't be too complicated to translate into whatever other language you're using, so long as it has a round() function and a random() function. (Keep in mind that Math.random() generates a number between 0 and 1; this is probably the only difference between languages.)

Hope it helps!