Floating point numbers not strings

gistfile1.js

function getFixed(mixed, precision)
{
    mixed     = '' + mixed;
    precision = precision || 2;

    var matches = mixed.match(/\d+\.?\d+/),
        amount  = (matches && matches[0]) || null,
        fixed   = parseFloat(amount).toFixed(precision);

    return parseFloat(fixed);
}

Number.prototype.asFixed = function(precision)
{
    return getFixed(this, precision);
}