为什么在Javascript中使用"class“时会出现语法错误

Question

我正在用javascript做一个游戏，我正在用一个类来保存所有的精灵。然而，当我尝试运行它时，safari给出了“类:保留字‘SyntaxError’的意外用法”。我找不到它应该这么做的理由。下面是我的代码：

var spritesContext;

//Sprite class
class sprite{
    constructor(imageName, imageX, imageY, imageHeight, imageWidth, context, canvas){
        this.imageName = imageName;
        this.imageX = imageX;
        this.imageY = imageY;
        this.imageHeight = imageHeight;
        this.imageWidth = imageWidth;
        this.canvas = canvas;
        this.context = context;
        spritesContext = context;
        console.log("Sprite constructed");
    }

    draw(){
        var character = new Image();
        character.src = "../Images/" + this.imageName + ".png";
        character.onload = function(){
            spritesContext.drawImage(character, this.imageX, this.imageY, this.imageWidth, this.imageHeight);
            console.log("Inner Draw is working.");
        }
        console.log("Draw is working.");
    }

    function getHeight(){
        return this.imageHeight;
    }

    function getWidth(){
         return this.imageWidth;
    }

    function getX(){
        return this.imageX;
    }

    function getY(){
       return this.imageY;
    }

    function moveUpX(e){
        this.imageX = (this.imageX + e);
    }

    function moveUpY(e){
        this.imageY = (this.imageY + e);
    }

    function moveBackX(e){
        this.imageX = (this.imageX - e);
    }

    function moveBackY(e){
       this.imageY = (this.imageY - e);
    }

    function changeImage(e){
        this.imageName = e;
    }

    function getImage(){
       return this.imageName;
    }

    function changeX(e){
         this.imageX = e;
    }

    function changeY(e){
        this.imageY = e;
    }

}

Answer 1

要使您的代码工作，更具体地说是关键字class，您需要在严格模式下启用某些浏览器来解释它。

要处于严格模式，请将以下内容添加到文件的顶部：

'use strict';

Answer 2

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当被问到这个问题时，Safari不支持"class“。