Round to 2 decimal places

Hi,

If you're new to JavaScript (or even an experienced user)it seems like  we all refer to rounding decimals incorrectly.

JavaScripting experts in the forums will ask you to specify if you really need to round up or down your decimal values with precission,  or,   to actually truncate the face value to only 2 digits to the right of the decimal period, simply because you won't be able to round up the real value with this method.

I am making this distinction because I've been corrected by ACP's and MVPs in the forums before. And I want to make sure I give you the appropriate answer.

For example, you can use a line of script like this for the event.value:

event.value = util.printf("%.2f", event.value);

This will resolve your immediate issue. But when you click with your mouse on that field, you'll notice that the real total decimal value is displayed.

Is this solution is what you're looking for?

Otherwise the real explanation to precission rounding is as imperfect as imperfect could be, and a real pain in the neck to work around with JavaScript.

A great explanation to this rounding problem is explained in great detail here:

• https://floating-point-gui.de/
• https://en.wikipedia.org/wiki/Rounding#Rounding_up

There are actually a few options for this. For example,

event.value = event.value.toFixed(2);

Or to create a rounded string.

event.value = util.printf("%,0.2f",event.value);

You can use this function to do it:

function myRound(v, nDecimals) {
	return Math.round(v * Math.pow(10, nDecimals)) / Math.pow(10, nDecimals);
}