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console 命令行工具 X clear

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

writedocument("数组创建........................")
var arr = ["HTML","CSS","JavaScript","jQuery","Vue.js"];

writedocument(arr);

writedocument("数组赋值........................")
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-------------------");
writedocument(arr.length);

writedocument("获取数组某一段-------------------");
writedocument(arr.slice(1,3));
writedocument("往数组头添加元素-------------------");
writedocument(arr.unshift("Web","Technoloy"));

writedocument("往数组尾添加元素-------------------");
writedocument(arr.push("B","s"));

writedocument("删除数组的第一个元素-------------------");
writedocument(arr.shift());

writedocument("删除数组的最后的一个元素-------------------");
var arr=["a","b","c","d"];
arr.pop();
writedocument(arr);

writedocument("对字符串数组按升序排序--------")
writedocument(arr.sort());

var numArr =[3,6,9,1,4,11];
writedocument("排序前:"+numArr);
function upcompare(x,y){
    if(x>y){
        return 1;
    }
    if(x==y){
        return 0;
    }
    if(x<y){
        return -1;
    }
}
numArr.sort(upcompare);
writedocument("升序排序后:"+numArr);
function downcompare(x,y){
    if(x>y){
        return -1;
    }
    if(x==y){
        return 0;
    }
    if(x<y){
        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("><"));

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("");
}
writedocument(addAngleBracket("绿叶学习网"));
<!DOCTYPE html> 
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
    <script>
      
    </script>
</head>
<body>
</body>
</html>