1.下面的代碼輸出多少？修改代碼讓fnArri 輸出 i。使用兩種以上的方法

<script>
    var fnArr = [];
    for (var i = 0; i < 10; i ++) {
        (function () {
            var s = i;
            fnArr[i] = function () {
                return s;
            };
        })()
    }
    console.log( fnArr[3]() );  //
</script>

<script>
    var fnArr = [];
    for (var i = 0; i < 10; i ++) {
        (function (n) {
            fnArr[i] = function () {
                return n;
            };
        })(i)
    }
    console.log( fnArr[3]() );  //
</script>

2.封裝一個汽車對象，可以通過如下方式獲取汽車狀態

<script>
    var Car = (function(){
       var speed = 0;
       function setSpeed(s){
           speed = s
       }

       function getSpeed () {
        return speed;
       }

       function accelerate () {
        return speed += 10;     
       }

       function decelerate () {
        return speed -= 10;     
       }

       function getStatus () {
        if (speed > 0) 
        {
            return 'running';
        }
        else
        {
            return 'stop';
        }
       }

       return {
          'setSpeed': setSpeed,
          'getSpeed': getSpeed,
          'accelerate': accelerate,
          'decelerate': decelerate,
          'getStatus': getStatus
       }
    })()
    Car.setSpeed(30);
    Car.getSpeed(); //30
    Car.accelerate();
    Car.getSpeed(); //40;
    Car.decelerate();
    Car.decelerate();
    Car.getSpeed(); //20
    Car.getStatus(); // 'running';
    Car.decelerate(); 
    Car.decelerate();
    Car.getStatus();  //'stop';
    //Car.speed;  //error
</script>

3.下面這段代碼輸出結果是? 為什么?

var a = 1;
setTimeout(function(){
    a = 2;
    console.log(a);
}, 0);
var a ;
console.log(a);
a = 3;
console.log(a);
/*1
  3
  2*/    //定時器的執行隊列問題

4.下面這段代碼輸出結果是? 為什么?

var flag = true;
setTimeout(function(){
    flag = false;
},0)
while(flag){}
console.log(flag);
//死循環，setTimeout在代碼解釋完后的隊列中

5.下面這段代碼輸出？如何輸出delayer: 0, delayer:1...（使用閉包來實現）

for(var i=0;i<5;i++){
    setTimeout(function(){
         console.log('delayer:' + i );
    }, 0);
    console.log(i);
}
/*
0
1
2
3
4
5:delayer:5
*/

<script>
    for(var i=0;i<5;i++){
        (function () {
            var n = i;
            setTimeout(function(){
                console.log('delayer:' + n );
            }, 0);
        })()
        console.log(i);
    }
</script>

6.如何獲取元素的真實寬高

• 主流瀏覽器：window.getComputesStyle

var style = window.getComputedStyle("元素", "偽類");

• 低版本IE：element.currentStyle

7.URL 如何編碼解碼？為什么要編碼？

• decodeURI()
• decodeURIComponent()
• encodeURI()
• encodeURIComponent()
  因為有些字符會引起歧義

8.補全如下函數，判斷用戶的瀏覽器類型

···
<script>
function isAndroid(){
return /Android/.test(navigator.userAgent);
}
function isIphone(){
return /iphone/.test(navigator.userAgent);
}
function isIpad(){
return /iPad/.test(navigator.userAgent);
}
function isIOS(){
return /(iPad)|(iPhone)/i.test(navigator.userAgent);
}
</script>
···