js數值四舍五入格式化
2024-04-27 15:08:54
供稿：網友
/* 將數值四舍五入后格式化. @param num 數值(Number或者String) @param cent 要保留的小數位(Number) @param isThousand 是否需要千分位 0:不需要,1:需要(數值類型); @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))//檢查傳入數值為數值類型. num = "0"; if(isNaN(cent))//確保傳入小數位為數值型數值. cent = 0; cent = parseInt(cent); cent = Math.abs(cent);//求出小數位數,確保為正整數. if(isNaN(isThousand))//確保傳入是否需要千分位為數值類型. isThousand = 0; isThousand = parseInt(isThousand); if(isThousand < 0) isThousand = 0; if(isThousand >=1) //確保傳入的數值只為0或1 isThousand = 1; sign = (num == (num = Math.abs(num)));//獲取符號(正/負數) //Math.floor:返回小于等于其數值參數的最大整數 num = Math.floor(num*Math.pow(10,cent)+0.50000000001);//把指定的小數位先轉換成整數.多余的小數位四舍五入. cents = num%Math.pow(10,cent); //求出小數位數值. num = Math.floor(num/Math.pow(10,cent)).toString();//求出整數位數值. cents = cents.toString();//把小數位轉換成字符串,以便求小數位長度. while(cents.length<cent){//補足小數位到指定的位數. cents = "0" + cents; } if(isThousand == 0) //不需要千分位符. return (((sign)?'':'-') + num + '.' + cents); //對整數部分進行千分位格式化. 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)); if(cents != 0){ return (((sign)?'':'-') + num + '.' + cents); } else { return (((sign)?'':'-') + num + '.00'); }}
