JS编写的贪吃蛇

来源：互联网发布：mysql truncate 权限编辑：程序博客网时间：2024/05/02 05:05

<!DOCTYPE html><html><head><meta charset="utf-8"><title>贪吃蛇</title></head><body><canvas id="can" width="400" height="400" style="background:Black"></canvas><script type="text/javascript">    var sn = [42, 41],dz = 43,fx = 1,n,ctx = document.getElementById("can").getContext("2d");function draw(t, c) {    ctx.fillStyle = c;    ctx.fillRect(t % 20 * 20 + 1, ~~ (t / 20) * 20 + 1, 18, 18);/*~~取反再取反：~~true == 1，~~false == 0其实是一种利用符号进行的类型转换,转换成数字类型*/}document.onkeydown = function(e) {    fx = sn[1] - sn[0] == (n = [ - 1, -20, 1, 20][(e || event).keyCode - 37] || fx) ? fx: n}; !function() {    sn.unshift(n = sn[0] + fx);    if (sn.indexOf(n, 1) > 0 || n < 0 || n > 399 || fx == 1 && n % 20 == 0 || fx == -1 && n % 20 == 19) return alert("GAME OVER");    draw(n, "Lime");    if (n == dz) {        while (sn.indexOf(dz = ~~ (Math.random() * 400)) >= 0);        draw(dz, "Yellow");    } else    draw(sn.pop(), "Black");    setTimeout(arguments.callee, 130);} ();</script></body></html>

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