Help with formula in javascript - figuring monthly payment

I know I must just be missing something really obvious, but this formula is coming up with a number close to accurate, but not quite - which is driving me nuts. What am I doing wrong?

I’m trying to have my script figure the monthly payments for a fixed-rate loan. I’m using (I think) a pretty standard formula:
Amortization-Calculation

Which I put into my script like this:

var m = l * ( (r * ((1 + +r)^360)) / (((1 + +r)^360) - 1) );

My variables have been defined earlier, some by user inputs, and are accurately displayed on the webpage so they seem to be working:

l = P above, loan total (starting principle) = 385000
r = r above, rate ([interest rate / 100] / 12) = 0.00315
360 = n above, loan periods (30 years * 12 months)

When I run it, it spits out “m” (A above) as 1206. It should be 1783. ??!!!

Any help would be greatly appreciated. Thank you!

PERFECT!!! It works now!!! Thank you so much!!!

var e = Math.pow((1 + +r), 360);
var m = l * ( (r * e) / (e - 1) );