Rounding down a calculation

[dougp300]

Hello Group, 

I am working on a converting a PDF to a fillable form. There are mulptiple equations that I have solved so far but I am stuck on this one. The calculation that I am using is figuring out how many trees per acre is needed. I have the field formatted to only show the integer, but in another calculation using the sum below, it adds the decimals to the end changing the final number Since I can not plant a fraction of a tree, I want to drop everything past the decimal. 

Thanks in advance, y'all are awesome! 

// Custom calculate script
// Get the field values, as numbers
var numerator = +getField("Spacing1").value;
var denominator = +getField("Spacing2").value;
// Calculate and set this field value
if (denominator !== 0) {event.value = 43560/(numerator * denominator);} else {event.value = "";}

[Nesa Nurani · Accepted solution]

To round down, you can use Math.floor(),

also, since you multiply numerator and denominator, you need to check that both are not 0.

Try this:

var numerator = Number(this.getField("Spacing1").valueAsString);
var denominator = Number(this.getField("Spacing2").valueAsString);

if (denominator !== 0 && numerator !== 0) {
event.value = Math.floor(43560/(numerator * denominator));} 
else {
event.value = "";}