How to write a prototype for Number.toFixed in JavaScript?

Question

I need to round decimal numbers to six places using JavaScript, but I need to consider legacy browsers so I can't rely on Number.toFixed

The big catch with toExponential, toFixed, and toPrecision is that they are fairly modern constructs not supported in Mozilla until Firefox version 1.5 (although IE supported the methods since version 5.5). While it's mostly safe to use these methods, older browsers WILL break so if you are writing a public program it's recommended you provide your own prototypes to provide functionality for these methods for older browser.

I'm considering using something like

Math.round(N*1000000)/1000000

What is the best method for providing this a prototype to older browsers?

Answer 1

Try this:

if (!Number.prototype.toFixed)

    Number.prototype.toFixed = function(precision) {
        var power = Math.pow(10, precision || 0);
        return String(Math.round(this * power)/power);
    }