//简易函数：求累加和

1 var num = 0;
2     function getnum(num1,num2) {
3         for (var num1 = num1;num1 <= num2;num1++){
4             num = num + num1;
5         }
6         console.log(num);
7     }
8     getnum(1,100);

//利用函数求最大值

 1 function bijiao(num1,num2){
 2         /* if (num1>num2){
 3              return num1;
 4          }else {
 5              return num2;
 6          }*/
 7 
 8          //也可以用三元表达式
 9          return num1>num2?num1:num2;
10      }
11      console.log(bijiao(100,50))

//利用函数求列表中的最大值

 1 function max(arr){
 2          var max1 = arr[0];
 3          for (var i = 1;i <= arr.length;i++){
 4              if(max1 < arr[i]){
 5                max1 = arr[i];
 6              }
 7          }
 8          return max1;
 9      }
10     var zhi = max([50,101,52,30,54,60,70]);
11      console.log(zhi);

//利用函数判断是否是闰年；

 1 function runnian(num) {
 2          if (num % 4 == 0 && num % 100 != 0){
 3              return '这是闰年';
 4          }else if(num % 400 == 0){
 5              return '这是闰年';
 6          }else {
 7              return '这不是闰年';
 8          }
 9      }
10      var run = runnian(2012);
11      console.log(run);