求n个数字的和,5 计算1+2+3+4+5

  //函数的声明function getSum(x) {if(x==1){return 1;}return x+getSum(x-1);}//函数的调用console.log(getSum(5));

求一个数字各个位数上的数字的和

//523function getEverySum(x) {if(x<10){return x;}//获取的是这个数字的个位数return x%10+getEverySum(parseInt(x/10));}console.log(getEverySum(1364));//5

求斐波那契数列

function getFib(x) {if(x==1||x==2){return 1}return getFib(x-1)+getFib(x-2);}console.log(getFib(12));

深拷贝

 //创建对象obj1var obj1={name:"东方不败",age:18,sex:"女",kongfu:["凌波微步","九阴神功","降龙十八掌","九阴白骨爪"],dog:{name:"大黄",age:18,sex:"女"}};//一个空的对象obj2var obj2={};//遍历函数，传入参数function extent(a,b) {for(var key in a){var  item=a[key];//判断a[key]的值是不是数组if(item instanceof Array ){b[key]=item;//递归调用extent(item,b[key]);}//判断是不是对象if (item instanceof Object){b[key]=item;extent(item,b[key]);}else {b[key]=item;}}}extent(obj1,obj2);console.log(obj1);console.log(obj2);