正确的JS四舍五入保留N为小数的算法怎么搞?
toFixed() 存在BUG
从网络上搜索了N种四舍五入的方法，经过测试都不太正确。
如：明明设置为保留两位小数，有时却出现了三位，而且计算结果，和人工计算结果有偏差。
[解决办法]
以下应该可以满足你
function roundTo(num, unit){ if(0 > unit) return num; unit = Math.pow(10,unit); return Math.round(num * unit) / unit; } function addZeros(){ var num = arguments[0],decimalSeparator = arguments[1],precision = arguments[2]; num = num.split(decimalSeparator); void 0 == num[1] && precision > 0 && (num[1] = "0"); return num[1].length < precision ? (num[1] += "0",this.addZeros(num[0] + decimalSeparator + num[1],decimalSeparator,precision)) : void 0 != num[1] ? num[0] + decimalSeparator + num[1] : num[0]; } function formatNumber(num, format){ num = roundTo(num,format.precision); var decimalSeparator = format.decimalSeparator, thousandsSeparator = format.thousandsSeparator, isMinus = 0 > num ? '-' : '', num = Math.abs(num), numStr = num.toString(); if(numStr.indexOf('e') == -1){ for(var numArr = numStr.split(decimalSeparator), i = "", k = numArr[0].toString(), j = k.length; 0 <= j; j -= 3){ i = j != k.length ? 0 != j ? k.substring(j - 3, j) + thousandsSeparator + i : k.substring(j - 3, j) + i : k.substring(j - 3, j); } numArr[1] && (i = i + decimalSeparator + numArr[1]); format.precision > 0 && "0" != i && (i = addZeros(i,decimalSeparator,format.precision)); } else{ i = h; } i = isMinus + i; return i; } alert(formatNumber(5.678,{ precision : 2, decimalSeparator : ".", thousandsSeparator : ","}));