js保留两位小数的函数有哪些

// 1.四舍五入 var num =2.446242342; num = num.toFixed(2); console.log(num); //2.45 console.log(typeof num); // string

// 2.不四舍五入 向下取整 num = Math.floor(num * 100) / 100; console.log(num); //2.44 console.log(typeof num); // number

// 3.不四舍五入 字符串匹配再转换 num = Number(num.toString().match(/^\d+(?:\.\d{0,2})?/)); console.log(num); //2.44 console.log(typeof num); // number

//4.四舍五入保留2位小数（若第二位小数为0，则保留一位小数） function keepTwoDecimal(num) { var result = parseFloat(num); if (isNaN(result)) { alert('传递参数错误，请检查！'); return false; } result = Math.round(num * 100) / 100; return result; }; keepTwoDecimal(num); console.log(num); //2.44 console.log(typeof num); //number

//5.四舍五入保留2位小数（不够位数，则用0替补） function keepTwoDecimalFull(num) { var result = parseFloat(num); if (isNaN(result)) { alert('传递参数错误，请检查！'); return false; } result = Math.round(num * 100) / 100; var s_x = result.toString(); //将数字转换为字符串 var pos_decimal = s_x.indexOf('.'); //小数点的索引值 // 当整数时，pos_decimal=-1 自动补0 if (pos_decimal < 0) { pos_decimal = s_x.length; s_x += '.'; } // 当数字的长度< 小数点索引+2时，补0 while (s_x.length <= pos_decimal + 2) { s_x += '0'; } return s_x; } console.log(keepTwoDecimalFull(120.5)); //120.50 console.log(typeof keepTwoDecimalFull(120.5)); //string console.log(keepTwoDecimalFull(2.446242342)); //2.45 console.log(typeof keepTwoDecimalFull(2.446242342)); //string

//浮点数保留两位小数 //1.功能：将浮点数四舍五入，取小数点后2位 function toDecimal(x) { var f = parseFloat(x); if (isNaN(f)) { return; } f = Math.round(x*100)/100; return f; } console.log(toDecimal(3.1465926)); // 3.15 console.log(typeof toDecimal(3.1415926)); //number

//2.强制保留2位小数，如：2，会在2后面补上00.即2.00 function toDecimal2(x) { var f = parseFloat(x); if (isNaN(f)) { return false; } var f = Math.round(x*100)/100; var s = f.toString(); var rs = s.indexOf('.'); if (rs < 0) { rs = s.length; s += '.'; } while (s.length <= rs + 2) { s += '0'; } return s; } console.log(toDecimal2(3.1)); // 3.10 console.log(typeof toDecimal2(3.1415926)); //string

// 3.保留两位小数 浮点数四舍五入 位数不够 不补0 function fomatFloat(src,pos){ return Math.round(src*Math.pow(10, pos))/Math.pow(10, pos); } console.log(fomatFloat(3.12645,2)); // 3.13 console.log(typeof fomatFloat(3.1415926)); //numbe