js 格式化数字（处理钱数时）

function formatCurrency(num) {if (!num)return "0.00";num = num.toString().replace(/\$|\,/g, '');//去除$符号if (isNaN(num))num = "0.00";sign = (num == (num = Math.abs(num)));num = Math.floor(num * 100 + 0.50000000001);cents = num % 100;num = Math.floor(num / 100).toString();if (cents < 10)cents = "0" + cents;for ( var i = 0; i < Math.floor((num.length - (1 + i)) / 3); i++)num = num.substring(0, num.length - (4 * i + 3)) + ','+ num.substring(num.length - (4 * i + 3));return (((sign) ? '' : '-') + '' + num + '.' + cents);
}