1     <script type="text/javascript" src="js/jquery-3.4.1.js"></script>

2     <script>

3         var cities = ["深圳市","广州市","珠海市","上海市","北京市"];

4         //jQuery对象调用遍历

5         $(cities).each(function(i,n) {

6             console.log(i+" = "+n);

7         });

8     </script>

1 <script>

2     //jQuery函数调用

3     $.each(cities,function(i,n) {

4         console.log(i+" > "+n);

5     });

6 </script>

 1 <script>

 2         var cities = ["深圳市","广州市","珠海市","上海市","北京市"]

 3

 4         function callback(i,n) {

 5             console.log("123：" + i + n);

 6         }

 7

 8         function foreach(array,callback) {

 9             for (var i = 0; i < array.length; i++) {

10                 var item = array[i];

11                 callback(i,item);

12             }

13         }

14         //调用

15         foreach(cities,callback);

16 </script>