JS 生成唯一数字

 1 function uniqueNumber() {
 2     var date = Date.now();
 3     
 4     if (date <= uniqueNumber.previous) {
 5         date = ++uniqueNumber.previous;
 6     } else {
 7         uniqueNumber.previous = date;
 8     }
 9 
10     return date;
11 }
12 
13 uniqueNumber.previous = 0;
14 
15 function ID(){
16   return uniqueNumber();
17 };