将数字转成货币字符串 ￥123,456,7.00

function setCurrency(num) {
	if(isNaN(num)) return '';
	num = parseFloat(num);
    var sign = '';
    var s;
    if (num < 0) {
        sign = '-';
        num *= -1;
    }
    s = num.toFixed(2).toString();
    s = s.replace(".", ",");
    var re = /(\d)(\d{3},)/;
    while (re.test(s))
        s = s.replace(re, "$1,$2");
    s = s.replace(/,(\d\d)$/, ".$1");
    return sign + '￥' + s.replace(/^\./, "0.");
}

function currencyValue(str) {
    var num = parseFloat(str.replace(/[,￥]/g, ''));
    if (isNaN(num))
        num = 0;
    return num;
}