Setting a decimal place without another function? 1

[JBruyet]

Hey all,

It's been a couple of years since my JavaScript class and I have a question. I have JS for figuring out a dollar amount and I can't find a way to have the answer drop to two decimal places without running a second function (I'm looking through my old code but I don't have anything there to help me). Here's what I have:

function doMath() {
var GasPrice = eval(document.Stuff.GasPrice.value)
var Mpg = eval(document.Stuff.Mpg.value)
var TripMiles = eval(document.Stuff.TripMiles.value)
var DaysWeek = eval(document.Stuff.DaysWeek.value)
var GasCost = TripMiles / Mpg * GasPrice * DaysWeek
alert("You're paying $" + GasCost + " to drive back and forth to work each week")
}

I think it'd be easier for people using this "calculator" if the answer didn't go out for 15 decimal places. Is there a way to limit the GasCost value to two decimal places without building a second function? If not, is toFixed the only way to go?

Thanks,

Joe Brouillette

 

[trollacious]

First, you don't need to eval() the form element values.

You can use the toFixed(NumberOfDecimalPlacesToDisplay) method to produce the results you want.

alert("You're paying $" + GasCost.toFixed(2) + " to drive back and forth to work each week");

Also, just for the sake of standards, I'd recommend using semicolons to terminate each line of code.

Lee

 

[JBruyet]

Thanks trollacious! I was putting the toFixed modifier in the wrong part of the code. I made your suggested change and it works great now. I think I'll even give you a star on this one 'cuz I look really good to the marketing department now.

And thanks for the suggestions as to the eval() and the semicolons.

Joe Brouillette