如何在Javascript中创建一个类？

这是我到目前为止所得到的,它根本不起作用:(我的播放器类中的所有变量都为null,并且永远不会调用更新.

我的意思是编程类,而不是css类. I.E.不是(.movingdiv {color：#ff0000;})

<!DOCTYPE html>
<html lang="en">
    <head>
        <title>Class Test</title>
        <Meta charset="utf-8" />
        <style>
            body { text-align: center; background-color: #ffffff;}
            #Box { position: absolute; left: 610px; top: 80px; height: 50px; width: 50px; background-color: #ff0000; color: #000000;}
        </style>

        <script type="text/javascript">
            document.onkeydown=function(event){keyDown(event)};
            document.onkeyup=function(event){keyUp(event)};
            var Box = 0;

            function Player () {
                var speed = 5;
                var x = 50;
                var y = 50;
            }

            function update() {
                Box.style.left = this.x + "px";
                Box.style.top = this.y + "px";
                Box.innerHTML = "<h6 style=\"margin: 0px 0px 0px 0px; padding: 0px 0px 0px 0px;\">X: "+ this.x + "<br /> Y: " + this.y + "</h6>";
            }

            var player = new Player();
            var keys = new Array(256);
            var i = 0;
            for (i = 0;i <= 256; i++){
                keys[i] = false;
            }

            function keyDown(event){
               keys[event.keyCode] = true;
            }

            function keyUp(event){
               keys[event.keyCode] = false; 
            }

            function update(){
                if(keys[37]) player.x -= player.speed;
                if(keys[39]) player.x += player.speed;

                player.update();
            }

            setInterval(update,1000/60);
        </script>
    </head>

    <body>
        <div id="Box" ></div> 
        <script type="text/javascript">
            Box = document.getElementById('Box');
            Box.innerHTML = "<h6 style=\"margin: 0px 0px 0px 0px; padding: 0px 0px 0px 0px;\">X: "+ player.x + "<br /> Y: " + player.y + "</h6>";
        </script>

    </body>
</html>

编辑：好吧,我想我搞砸了.我第一次尝试上课时似乎搞砸了.重试后,我似乎能够在Meders帖子中使用“1 Using a function”.

真正的问题似乎是javascript在我的实际代码中到达这一行时不知道该怎么做：

Box.style.background-position = "" + -(this.frame * this.width) + "px " + -(this.state * this.height) + "px";

我放的时候似乎也会窒息

Box.style.background色

所以我现在需要回答的问题是如何在javascript中设置一个样式变量,名称中带有“ – ”.我会在一秒钟内发布测试

解决方法

根据 this 文章,有三种方法可以在JavaScript中定义类：

1使用功能

例：

function Apple (type) {
     this.type = type;
     this.color = "red";
     this.getInfo = getAppleInfo;
 }

 function getAppleInfo() {
     return this.color + ' ' + this.type + ' apple';
 }


 var apple = new Apple('macintosh');
 apple.color = "reddish";
 alert(apple.getInfo());

2使用JSON

var apple = {
     type: "macintosh",color: "red",getInfo: function () {
         return this.color + ' ' + this.type + ' apple';
     }
 }


 apple.color = "reddish";
 alert(apple.getInfo());

3单身使用功能

var apple = new function() {
     this.type = "macintosh";
     this.color = "red";
     this.getInfo = function () {
         return this.color + ' ' + this.type + ' apple';
     };
 }


 apple.color = "reddish";
 alert(apple.getInfo());

原文地址：https://www.jb51.cc/js/156446.html

如何在Javascript中创建一个类？

解决方法

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