js的数组

var cars = ["Banana", "Orange", "Apple", "Mango"];

var x = cars.length; // length 属性返回元素的数量
var y = cars.sort(); // sort() 方法对数组进行排序

var first = cars[0];  访问数组

cars.length  获取数组长度

数组操作 

https://www.w3school.com.cn/js/js_arrays.asp

数组方法

https://www.w3school.com.cn/js/js_array_methods.asp

操作数组

https://www.w3school.com.cn/js/js_array_sort.asp

遍历数组

https://www.w3school.com.cn/js/js_array_iteration.asp

for or whil遍历的方法

https://www.w3school.com.cn/js/js_loop_for.asp

https://www.w3school.com.cn/js/js_loop_while.asp

判断是否为数组的方法

https://www.w3school.com.cn/js/js_type_conversion.asp

var fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo").innerHTML = isArray(fruits);

function isArray(myArray) {
return myArray.constructor === Array;
}

骚写法遍历数组

<p id="demo"></p>

<script>
var cars = ["BMW", "Volvo", "porsche", "Ford"];
var i = 0;
var text = "";
for (;cars[i];) {
text += cars[i] + "<br>";
i++;
}
document.getElementById("demo").innerHTML = text;
</script>

第二种

<p id="demo"></p>

<script>
var cars = ["BMW", "Volvo", "porsche", "Ford"];
var i = 0;
var text = "";
while (cars[i]) {
text += cars[i] + "<br>";
i++;
}
document.getElementById("demo").innerHTML = text;
</script>