每隔三位添加一个逗号（小数点/整数都适合）

 1  addCommas:function(nStr)
 2     {
 3         nStr += \'\';
 4         x = nStr.split(\'.\');
 5         x1 = x[0];
 6         x2 = x.length > 1 ? \'.\' + x[1] : \'\';
 7         var rgx = /(\d+)(\d{3})/;
 8         while (rgx.test(x1)) {
 9         x1 = x1.replace(rgx, \'$1\' + \',\' + \'$2\');
10         }
11         return x1 + x2;
12     }

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