原生JavaScript实现贪吃蛇游戏的具体代码，供大家参考，具体内容如下
代码：
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var timer = null;
var oMain = document.getElementById(main);
function Map(atom,xnum,ynum){//地图,设置单位大小，及根据单位大小创建地图
this.atom = atom;
this.xnum = xnum;
this.ynum = ynum;
this.create = function(){
this.canvas = document.createElement(
