Javascript内存游戏-图像交换

这是我正在开发的内存游戏的当前代码。我使用的是纯JavaScript，我的a标签的onclick函数有问题。我想要的是游戏将点击的图像（问号）与分配给点击图像的类名的图像进行交换，从而产生翻转效果。

我目前得到的是，无论我点击哪里，只有最后一个图像会被交换。

"use strict"
var newDiv = null;
var innerDiv = null;
var table = null;
var row = null;
var cell = null;
var aTag = null;
var image = null;
// Use this to put class names on the images.
var boxCounter = 0;
// Static memory-object.
var Memory = {
    memoryArray: [],
    init: function (e) {
        // Calls a separate js-file which generates a random numbers.
        Memory.memoryArray = RandomGenerator.getPictureArray(4, 4);
        // Calls the rendering method
        Memory.renderArray(Memory.memoryArray);
    },
    renderArray: function (myArray) {
        // Creates and places div-tags in the HTML-document.
        newDiv = document.createElement("div");
        document.getElementsByTagName("body")[0].appendChild(newDiv);
        innerDiv = document.createElement("div");
        newDiv.appendChild(innerDiv);
        // Creates a table and places it in the HTML-document.
        table = document.createElement("table");
        table.border = 1;
        // Generates rows and cells, swap the 4's to change the size of the gameboard.
        for (var i = 0; i < 4; ++i) {
            row = document.createElement("tr");
            table.appendChild(row);
            // Creates a cell, each with its own respective random number.
            for (var j = 0; j < 4; ++j) {
                cell = document.createElement("td");
                // Adds a "Question-mark"-picture to the cell and places them in a-tags.
                image = document.createElement("img");
                image.className = myArray[i * 4 + j];
                image.src = "https://github.com/1dv403/1dv403-laborationer/blob/master/3-gameon/memory/pics/0.png?raw=true";
                aTag = document.createElement("a");
                aTag.onclick = function () {
                    Memory.flipTile(image.className);
                };
                // Places the pictures in the document, along with its random number for easier testing purposes.
                aTag.appendChild(document.createTextNode(myArray[i * 4 + j]));
                aTag.appendChild(image);
                cell.appendChild(aTag);
                row.appendChild(cell);
            };
        };
        innerDiv.appendChild(table);
    },
    flipTile: function (imageClass) {
        console.log(imageClass);
        // This should flip the tiles if the number matches the class name.
        if (imageClass == 1) {
            image.src = "https://github.com/1dv403/1dv403-laborationer/blob/master/3-gameon/memory/pics/1.png?raw=true";
        };
        if (imageClass == 2) {
            image.src = "https://github.com/1dv403/1dv403-laborationer/blob/master/3-gameon/memory/pics/2.png?raw=true";
        };
        if (imageClass == 3) {
            image.src = "https://github.com/1dv403/1dv403-laborationer/blob/master/3-gameon/memory/pics/3.png?raw=true";
        };
        if (imageClass == 4) {
            image.src = "https://github.com/1dv403/1dv403-laborationer/blob/master/3-gameon/memory/pics/4.png?raw=true";
        };
        if (imageClass == 5) {
            image.src = "https://github.com/1dv403/1dv403-laborationer/blob/master/3-gameon/memory/pics/5.png?raw=true";
        };
        if (imageClass == 6) {
            image.src = "https://github.com/1dv403/1dv403-laborationer/blob/master/3-gameon/memory/pics/6.png?raw=true";
        };
        if (imageClass == 7) {
            image.src = "https://github.com/1dv403/1dv403-laborationer/blob/master/3-gameon/memory/pics/7.png?raw=true";
        };
        if (imageClass == 8) {
            image.src = "https://github.com/1dv403/1dv403-laborationer/blob/master/3-gameon/memory/pics/8.png?raw=true";
        };
    }
};
window.onload = Memory.init;