//千分位分割 function toThousands(num) {
       var result = '', counter = 0;     num = (num || 0).toString();     for (var i = num.length - 1; i >= 0; i--) {
           counter++;         result = num.charAt(i) + result;         if (!(counter % 3) && i != 0) { result = ',' + result; }     }     return result; } function renderNum(num){
       var cur_num = null;     var string_num = (num||0).toString();     var spot_index = string_num.indexOf('.');     if(spot_index == -1){
           cur_num = toThousands(num);     }else{
           var cur_spot_num = string_num.substring(spot_index);         num = string_num.substring(0,spot_index);         cur_num = toThousands(num);         cur_num = cur_num+cur_spot_num;     }     return cur_num } renderNum(1234.45);