Why is toFixed Not Rounding Values Accurately in Javascript?

toFixed Not Rounding Accurately in Javascript

In the context of managing checkbox values in Javascript, users may encounter a challenge where the toFixed(2) method does not round values appropriately. For example, a value of 859.385 may display as 859.38 instead of the expected 859.39.

Browser Inconsistencies and Precision

It's important to note that the toFixed method can behave differently based on the browser being used. To address browser inconsistencies and ensure consistent rounding across browsers, the recommended solution is to utilize the toFixed10 method or the following custom function:

<code class="javascript">function toFixed( num, precision ) {
    return (+(Math.round(+(num + 'e' + precision)) + 'e' + -precision)).toFixed(precision);
}</code>

Custom Function Implementation

Incorporating the custom toFixed function in the provided code would require the following modification:

<code class="javascript">var standardprice = parseFloat($('#hsprice_'+this.id.split('_')[1]).val());
var price =  parseFloat($('#hprice_'+this.id.split('_')[1]).val());
var discount =  parseFloat($('#hdiscount_'+this.id.split('_')[1]).val());
var deposit =  parseFloat($('#hdeposit_'+this.id.split('_')[1]).val());

var currSprice = parseFloat($('#hTotalSprice').val());
var currPrice = parseFloat($('#hTotalPrice').val());
var currDiscount = parseFloat($('#hTotalDiscount').val());
var currDeposit = parseFloat($('#hTotalDeposit').val());

currSprice += standardprice;
currPrice += price;
currDiscount += discount;
currDeposit += deposit;

$('#lblTotalSprice').text('$'+addCommas(toFixed(currSprice, 2)));
$('#lblTotalPrice').text('$'+addCommas(toFixed(currPrice, 2)));
$('#lblTotalDiscount').text('$'+addCommas(toFixed(currDiscount, 2)));
$('#lblTotalDeposit').text('$'+addCommas(toFixed(currDeposit, 2)));

$('#hTotalSprice').val(toFixed(currSprice, 2));
$('#hTotalPrice').val(toFixed(currPrice, 2));
$('#hTotalDiscount').val(toFixed(currDiscount, 2));
$('#hTotalDeposit').val(toFixed(currDeposit, 2));</code>

By implementing this custom function, you can ensure accurate rounding regardless of browser variations.

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