formatting calculated values

Hi Experts,

i am having a problem with values calculated on the fly!
In Javascript On load (add page) i calculate some values ex.

ctrlfscrap.setValue(((Number(ctrlfnetto.getValue()) * 0.40) / 36) * Number(ctrlfleasperiode.getValue()));

After calculation the value shown are ex. 60456.456789 - how do i format the value to 60456.46 ??

Thanks in advance

Michael