2月5

var length=10;
function fn(){
console.log(this.length)
}
var obj={
length:5,
method:function(fn){
fn();
arguments[0]();
}
}
obj.method(fn,1)

结果为10 ，2

 

2 (function test(){
var a=b=5;
alert(typeof a)
alert(typeof b)

})()
alert(typeof a)
alert(typeof b)

结果为 number number undefined number

3 console.log(square(5));
var square=function(n){
return n*n
}

报错

4for(var i=1;i<=5;i++){
setTimeout(() => {
console.log(i)
}, 1000);
}

 

结果为6

5for(var i=1;i<=5;i++){
(function (i){
setTimeout(() => {
console.log(i)
}, 1000);
})(i)
}
结果为 1 2 3 4 5