SOURCE

function writeDocument(variable){
    document.write(variable+"<br/>");
}
var arr = [3, 1, 2, 4, 5, 6];
writeDocument("获取数组的长度-------------------------");
document.write(arr.length + "<br/>");

writeDocument("获取数组的1-2号元素----------------------------");
document.write(arr.slice(1, 3) + "<br/>");

writeDocument("往数组头添加元素----------------------------");
arr.unshift(0);
document.write(arr+ "<br/>");

writeDocument("往数组尾部添加元素----------------------------");
arr.push(7);
document.write(arr+ "<br/>");


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

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

writeDocument("对字符串进行升序的排序--------------");
writeDocument(arr.sort());

function downCompare(left,right){
    if(left-right>0){
        return -1;
    }
    if(left-right==0){
        return 0;
    }
    if(left-right<0){
        return 1;
    }
}

function upCompare(left,right){
    if(left-right>0){
        return 1;
    }
    if(left-right==0){
        return 0;
    }
    if(left-right<0){
        return -1;
    }
}

writeDocument("打印排序前的数字数组："+ arr);
writeDocument("打印降序后的数字数组："+ arr.sort(downCompare));
writeDocument("打印升序后的数字数组："+ arr.sort(upCompare));

writeDocument("反转数组-------------");
writeDocument(arr.reverse());
writeDocument(arr.join(":"));
writeDocument(arr.join("<"));

writeDocument("给字符添加尖括号--------");

var strValue = "绿叶学习网";
var str = strValue.split("").join("><");
var arr1 = str.split("");
arr1.unshift("<");
arr1.push(">");
var result = arr1.join("");
document.write(result);