将数值四舍五入(保留2位小数)后格式化成金额形式

/**
* 将数值四舍五入(保留2位小数)后格式化成金额形式
*
* @param num 数值(Number或者String)
* @return 金额格式的字符串,如'1,234,567.45'
* @type String
*/
function formatCurrency(num) {
num = num.toString().replace(/\$|\,/g,'');
if(isNaN(num))
num = "0";
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);
}