console 命令行工具 X clear

console

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

//数组的赋值
var arr=["HTML","CSS","Javascript","JQuery","Vue.js"];

writeDocument(arr[2]);

writeDocument(arr);

arr[4]="React.js";

writeDocument(arr);

arr[5]="Vue.js";

writeDocument(arr);

arr[8]="Angular.js";

writeDocument(arr);

writeDocument("-------------------获取数组长度-------------------");
document.write("数组长度为"+arr.length+'<br/>');

writeDocument("-------------------获取数组某一层-------------------");
document.write(arr.slice(2,9)+'<br/>');

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

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

writeDocument("-------------------删除数组第一个元素-------------------");
arr.shift();
document.write(arr+'<br/>');

writeDocument("-------------------删除数组最后一个元素-------------------");
arr.pop();
document.write(arr+'<br/>');


writeDocument("-------------------对字符串数组进行排序-------------------");
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);
writeDocument("升序排序后："+numArr);
function downcompare(l,r){
    if(l>r){
        return -1;
    }
    if(l==r){
        return 0;
    }
    if(l<r){
        return 1;
    }
}
numArr.sort(downcompare);
writeDocument("降序排序后："+numArr);

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

writeDocument("-------------------<绿叶学习网>-------------------");
function addAngleBracket(strValue){
    var strArr=strValue.split("");
    console.log(strArr);
    var str=strArr.join("><");
    console.log(str);
    strArr=str.split("");
    console.log(strArr);
    strArr.unshift("<");
    strArr.push(">");
    console.log(strArr);
    return strArr.join("");
    /*var str="绿叶学习网";
    var str1=str.split("").join("><");
    var str2=str1.split("");
    str2.unshift("<");
    str2.push(">");
    var str3=str2.join("");
    document.write(str3);*/
}
document.write(addAngleBracket("绿叶学习网"));

<!DOCTYPE html> 
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
    <script>
    </script>
</head>
<body>
</body>
</html>