## 1、 [4, 5, 6] ; ["張三", 2, 3] funciton fn(arr){ arr[0] = '張三' //修改全局對象arr arr = [4,5,6] //修改argument對象 console.log(arr) //argument對象 } var arr = [1,2,3] fn(arr) console.log(arr) //全局對象 ## 2、 5；5 function fn(){ var a = b = 5 console.log(a) console.log(b) } fn() ## 3、 0；5 function fn(){ console.log(a) console.log(b) var a = b = 5 //提升到頂部 => b=5；var a=b => b是全局對象，a是內部對象 } fn() ## 4、 5 function fn(a){ function fn(a){ console.log(a) => var a; var a = 10 console.log(a) } a = 10 fn(5) } ## 5、? a( ){console.log(a)} ；1 var a = 1; function fn(a){ console.log(a) var a = 2 function a( ){ console.log(a) } console.log(this.a) // this=>全局對象 a( ) } fn(3) ## 6、使用遞歸方法計算 1+2+3+4+5=15 [[https://juejin.im/entry/594a48395c497d006b0dfcf6](https://juejin.im/entry/594a48395c497d006b0dfcf6)] function sum(n){ if(n==1) return 1; return sum(n-1) + n; }