Convert Fraction String to Decimal?

Since no one has mentioned it yet there is a quick and dirty solution:

var decimal = eval(fraction); 

Which has the perks of correctly evaluating all sorts of mathematical strings.

eval("3/2")    // 1.5
eval("6")      // 6
eval("6.5/.5") // 13, works with decimals (floats)
eval("12 + 3") // 15, you can add subtract and multiply too

People here will be quick to mention the dangers of using a raw eval but I submit this as the lazy mans answer.