/*
將數(shù)值四舍五入后格式化.
@param num 數(shù)值(Number或者String)
@param cent 要保留的小數(shù)位(Number)
@param isThousand 是否需要千分位 0:不需要,1:需要(數(shù)值類型);
@return 格式的字符串,如'1,234,567.45'
@type String
*/
function formatNumber(num,cent,isThousand){
num = num.toString().replace(/\$|\,/g,'');
if(isNaN(num))//檢查傳入數(shù)值為數(shù)值類型.
num = "0";
if(isNaN(cent))//確保傳入小數(shù)位為數(shù)值型數(shù)值.
cent = 0;
cent = parseInt(cent);
cent = Math.abs(cent);//求出小數(shù)位數(shù),確保為正整數(shù).
if(isNaN(isThousand))//確保傳入是否需要千分位為數(shù)值類型.
isThousand = 0;
isThousand = parseInt(isThousand);
if(isThousand < 0)
isThousand = 0;
if(isThousand >=1) //確保傳入的數(shù)值只為0或1
isThousand = 1;
sign = (num == (num = Math.abs(num)));//獲取符號(hào)(正/負(fù)數(shù))
//Math.floor:返回小于等于其數(shù)值參數(shù)的最大整數(shù)
num = Math.floor(num*Math.pow(10,cent)+0.50000000001);//把指定的小數(shù)位先轉(zhuǎn)換成整數(shù).多余的小數(shù)位四舍五入.
cents = num%Math.pow(10,cent); //求出小數(shù)位數(shù)值.
num = Math.floor(num/Math.pow(10,cent)).toString();//求出整數(shù)位數(shù)值.
cents = cents.toString();//把小數(shù)位轉(zhuǎn)換成字符串,以便求小數(shù)位長(zhǎng)度.
while(cents.length<cent){//補(bǔ)足小數(shù)位到指定的位數(shù).
cents = "0" + cents;
}
if(isThousand == 0) //不需要千分位符.
return (((sign)?'':'-') + num + '.' + cents);
//對(duì)整數(shù)部分進(jìn)行千分位格式化.
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);
}