ohgod.js

 function decimalAdjust(type, value, exp) {
                // If the exp is undefined or zero...
                if (typeof exp === 'undefined' || +exp === 0) {
                    return Math[type](value);
                }
                value = +value;
                exp = +exp;
                // If the value is not a number or the exp is not an integer...
                if (isNaN(value) || !(typeof exp === 'number' && exp % 1 === 0)) {
                    return NaN;
                }
                // Shift
                value = value.toString().split('e');
                value = Math[type](+(value[0] + 'e' + (value[1] ? (+value[1] - exp) : -exp)));
                // Shift back
                value = value.toString().split('e');
                return +(value[0] + 'e' + (value[1] ? (+value[1] + exp) : exp));
            }

            // Decimal round
            if (!Math.round10) {
                Math.round10 = function (value, exp) {
                    return decimalAdjust('round', value, exp);
                };
            }
            // Decimal floor
            if (!Math.floor10) {
                Math.floor10 = function (value, exp) {
                    return decimalAdjust('floor', value, exp);
                };
            }
            // Decimal ceil
            if (!Math.ceil10) {
                Math.ceil10 = function (value, exp) {
                    return decimalAdjust('ceil', value, exp);
                };
            }
        }