数组API的用法和意思

1.toString()将数组转为字符串并返回。

      <p id="demo">点击按钮将数组转为字符串并返回。</p>
        <button onclick="myFunction()">点我</button>
        <script>
            function myFunction(){
                var fruits = ["Banana", "Orange", "Apple", "Mango"];
                var str = fruits.toString();
                var x=document.getElementById("demo");
                x.innerHTML= str;
            }

2.slice()截取数组下标 1 到 2 的元素

<p id="demo">点击按钮截取数组下标 1 到 2 的元素。</p>
        <button onclick="myFunction()">点我</button>
        <script>
            function myFunction(){
                var fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];
                var citrus = fruits.slice(1,3);
                var x=document.getElementById("demo");
                x.innerHTML=citrus;
            }
        </script>

3.unshift()在数组中插入元素

 <p id="demo">单击按钮在数组中插入元素。</p>
            <button onclick="myFunction()">点我</button>
            <script>
                function myFunction(){
                    var fruits = ["Banana", "Orange", "Apple", "Mango"];
                    fruits.unshift("Lemon","Pineapple");
                    var x=document.getElementById("demo");
                    x.innerHTML=fruits;
                }
            </script>

4.splice()向数组添加元素

<p id="demo">点击按钮向数组添加元素。</p>
        <button onclick="myFunction()">点我</button>
        <script>
            function myFunction(){
                var fruits = ["Banana", "Orange", "Apple", "Mango"];
                fruits.splice(2,0,"Lemon","Kiwi");
                var x=document.getElementById("demo");
                x.innerHTML=fruits;
            }
        </script>

5.reverse()将数组反转排序

<p id="demo">单击按钮将数组反转排序。</p>
        <button onclick="myFunction()">点我</button>
        <script>
            var fruits = ["Banana", "Orange", "Apple", "Mango"];
            function myFunction(){
                fruits.reverse();
                var x=document.getElementById("demo");
                x.innerHTML=fruits;
            }
        </script>

6.push()给数组添加新的元素

<p id="demo">单击按钮给数组添加新的元素。</p>
        <button onclick="myFunction()">点我</button>
        <script>
            var fruits = ["Banana", "Orange", "Apple", "Mango"];
            function myFunction(){
                fruits.push("Kiwi")
                var x=document.getElementById("demo");
                x.innerHTML=fruits;
            }
        </script>

7.pop()移除最后一个数组元素

p id="demo">单击按钮删除数组的最后一个元素。</p>
    <button onclick="myFunction()">点我</button>
    <script>
        var fruits = ["Banana", "Orange", "Apple", "Mango"];
        function myFunction(){
            fruits.pop();
            var x=document.getElementById("demo");
            x.innerHTML=fruits;
        }
    </script>

8.join('')把数组中的所有元素转换为一个字符串

<p id="demo">点击按钮将数组作为字符串输出。</p>
     <button onclick="myFunction()">点我</button>
    <script>
        function myFunction(){
            var fruits = ["Banana", "Orange", "Apple", "Mango"];
            var x=document.getElementById("demo");
            x.innerHTML=fruits.join(" and ");
        }
    </script>

9.concat()把两个数组拼接起来

   var hege = ["Cecilie", "Lone"];
    var stale = ["Emil", "Tobias", "Linus"];
    var children = hege.concat(stale);
    document.write(children);

10.shife的用法.移除一个东西

var fruits = ["Banana", "Orange", "Apple", "Mango"];
    fruits.shift('Banana')
    document.write(fruits)