JavaScript 格式化数字 - 转

 1 function number_format(number, decimals, dec_point, thousands_sep,roundtag) {
 2     /*
 3     * 参数说明：
 4     * number：要格式化的数字
 5     * decimals：保留几位小数
 6     * dec_point：小数点符号
 7     * thousands_sep：千分位符号
 8     * roundtag:舍入参数，默认 "ceil" 向上取,"floor"向下取,"round" 四舍五入
 9     * */
10     number = (number + ‘‘).replace(/[^0-9+-Ee.]/g, ‘‘);
11     roundtag = roundtag || "ceil"; //"ceil","floor","round"
12     var n = !isFinite(+number) ? 0 : +number,
13         prec = !isFinite(+decimals) ? 0 : Math.abs(decimals),
14         sep = (typeof thousands_sep === ‘undefined‘) ? ‘,‘ : thousands_sep,
15         dec = (typeof dec_point === ‘undefined‘) ? ‘.‘ : dec_point,
16         s = ‘‘,
17         toFixedFix = function (n, prec) {
18  
19             var k = Math.pow(10, prec);
20             console.log();
21  
22             return ‘‘ + parseFloat(Math[roundtag](parseFloat((n * k).toFixed(prec*2))).toFixed(prec*2)) / k;
23         };
24     s = (prec ? toFixedFix(n, prec) : ‘‘ + Math.round(n)).split(‘.‘);
25     var re = /(-?\d+)(\d{3})/;
26     while (re.test(s[0])) {
27         s[0] = s[0].replace(re, "$1" + sep + "$2");
28     }
29  
30     if ((s[1] || ‘‘).length < prec) {
31         s[1] = s[1] || ‘‘;
32         s[1] += new Array(prec - s[1].length + 1).join(‘0‘);
33     }
34     return s.join(dec);
35 }
36 console.log(number_format(2, 2, ".", ","))//"2.00"
37 console.log(number_format(3.7, 2, ".", ","))//"3.70"
38 console.log(number_format(3, 0, ".", ",")) //"3"
39 console.log(number_format(9.0312, 2, ".", ","))//"9.03"
40 console.log(number_format(9.00, 2, ".", ","))//"9.00"
41 console.log(number_format(39.715001, 2, ".", ",", "floor")) //"39.71"
42 console.log(number_format(9.7, 2, ".", ","))//"9.70"
43 console.log(number_format(39.7, 2, ".", ","))//"39.70"
44 console.log(number_format(9.70001, 2, ".", ","))//"9.71"
45 console.log(number_format(39.70001, 2, ".", ","))//"39.71"
46 console.log(number_format(9996.03, 2, ".", ","))//"9996.03"
47 console.log(number_format(1.797, 3, ".", ",", "floor"))//"1.797"