Convert a formatted number from a text box to an actual decimal

Convert a formatted number from a text box to an actual decimal

I need to do some math against a number in a text box client. Don't really know JQuery at all so this is probably an easy question, but I need to convert a value in a text box (e.g. '100,000.00') into an actual decimal value. Can somebody point me in the right direction to do this? Thanks.