var a = 2221222122.675414
var b = a.toFixed(a.toString().split(".")[1].length).replace(/(\d)(?=(\d{3})+\.)/g, '$1,');//使用正则替换,每隔三个数加一个','
console.log(b) //2,221,222,122.675414
var a = 2221222122.675414
var b = a.toFixed(a.toString().split(".")[1].length).replace(/(\d)(?=(\d{3})+\.)/g, '$1,');//使用正则替换,每隔三个数加一个','
console.log(b) //2,221,222,122.675414