SOURCE

function writeDocument(variable){
    document.write(variable+"<br/>");
}

writeDocument("数组的创建----------------------------")
var arr = ["HTML","CSS","JavaScript","jQuery","Vue.js"]; 
writeDocument(arr);

writeDocument("数组下标取值----------------------------")
writeDocument(arr[2]);

writeDocument("数组赋值----------------------------")

arr[4]="React.js";
writeDocument(arr);
arr[5]="Vue.js";
writeDocument(arr);
arr[8]="Angular.js";
writeDocument(arr);

var arr1=[1,2,3];
var arr2=[4,5,6,7,8,9];
writeDocument("获取数组的长度----------------------------")
document.write(arr1.length+"<br/>");
document.write(arr2.length+"<br/>");

writeDocument("获取数组某一段----------------------------")
document.write(arr2.slice(1,3)+"<br/>");

writeDocument("往数组头添加元素----------------------------")
arr1.unshift("7");
document.write(arr1+"<br/>");

writeDocument("往数组尾添加元素----------------------------")
arr1.push("9");
document.write(arr1+"<br/>");


writeDocument("删除数组的第一个元素----------------------------")
arr2.shift();
document.write(arr2+"<br/>");

writeDocument("删除数组的最后一个元素----------------------------")
arr2.pop();
document.write(arr2+"<br/>");

var arr = ["HTML","CSS","JavaScript","jQuery","Vue.js"]; 

writeDocument("对字符串数组按升序排序----------------------------")
document.write(arr.sort()+"<br/>");

var numArr=[3,6,9,1,4,11];

document.write("排序前： "+numArr+"<br/>");
function upcompare(l,r){
    if(l>r){
        return 1;
    }
    if(l=r){
        return 0;
    }
    if(l<r){
        return -1;
    }
}
numArr.sort(upcompare);
document.write("升序排序后： "+numArr+"<br/>");

function downcompare(l,r){
    if(l>r){
        return -1;
    }
    if(l=r){
        return 0;
    }
    if(l<r){
        return 0;
    }
}
numArr.sort(downcompare);
document.write("降序排序后： "+numArr+"<br/>");

writeDocument("反转数组----------------------------")
document.write("反转数组:"+numArr.reverse()+"<br/>");
document.write("默认join数组:"+numArr.join()+"<br/>");
document.write("默认join数组:"+numArr.join(":")+"<br/>");
document.write("默认join数组:"+numArr.join("-")+"<br/>");
document.write("默认join数组:"+numArr.join("><")+"<br/>");

writeDocument("题1----------------------------")

var arr = ["HTML","CSS","JavaScript","jQuery","Vue.js"];