theMatrix代码雨效果

做了一个代码雨效果放在个人主页: https://lanleilin.github.io/lanGallery/index.html
代码：
<!DOCTYPE html>
<html>

    <head>
        <title>The Matrix</title>
        <script type="text/javascript" src="../js/jquery.min.js">
        </script>
        <meta charset="utf-8">
        <script>
            $(document).ready(function() {
                //判断移动端还是PC端
                function isPC() {
                    var userAgentInfo = navigator.userAgent;
                    var Agents = ["Android", "iPhone", "SymbianOS", "Windows Phone", "iPad", "iPod"];
                    var flag = true;
                    for(var v = 0; v < Agents.length; v++) {
                        if(userAgentInfo.indexOf(Agents[v]) > 0) {
                            flag = false;
                            break;
                        }
                    }
                    return flag;
                }

                if(!isPC()) {
                    // 手机
                    var s = window.screen;
                    console.log(s);
                    var width = s.width * 2.5;
                    q.width = s.width * 2.5;
                    q.Height = 300;
                    var height = q.height;
                    var yPositions = Array(300).join(0).split('');
                    var ctx = q.getContext('2d');
                    var draw = function() {
                        ctx.fillStyle = 'rgba(0,0,0,.05)'; //反复生成opacity为0.5的半透明黑色背景
                        ctx.fillRect(0, 0, width, height);
                        ctx.fillStyle = 'lightgreen';
                        ctx.font = '3rem Georgia';
                        yPositions.map(function(y, index) {
                            text = String.fromCharCode(1e2 + Math.random() * 33); //随机生成字母
                            x = (index * 30) + 10; //x距离
                            q.getContext('2d').fillText(text, x, y); //在指定位置显示一个字母
                            if(y > Math.random() * 1e4) {
                                yPositions[index] = 0;
                            } else {
                                yPositions[index] = y + 20; //确定显示字母的位置
                            }
                        });
                    };
                    RunMatrix();

                    function RunMatrix() {
                        Game_Interval = setInterval(draw, 50); //设定刷新间隔
                    }
                } else {
                    var s = window.screen;
                    //      var q=$('#q');
                    console.log(typeof($("#q")));
                    console.log(document.getElementById("q"));

                    var width = q.width = s.width;
                    var height = q.height;
                    var yPositions = Array(300).join(0).split('');
                    var ctx = q.getContext('2d');
                    var draw = function() {
                        ctx.fillStyle = 'rgba(0,0,0,.05)';
                        ctx.fillRect(0, 0, width, height);
                        ctx.fillStyle = 'red';
                        ctx.font = '10pt Georgia';
                        yPositions.map(function(y, index) {
                            text = String.fromCharCode(1e2 + Math.random() * 33);
                            x = (index * 10) + 10; //x距离
                            q.getContext('2d').fillText(text, x, y);
                            if(y > Math.random() * 1e4) {
                                yPositions[index] = 0;
                            } else {
                                yPositions[index] = y + 10;
                            }
                        });
                    };
                    RunMatrix();

                    function RunMatrix() {
                        Game_Interval = setInterval(draw, 50);
                    }
                }
                isPC();
            });
        </script>
    </head>

    <body>
        <div align="center">
            <h1 id="theMatrix">The matrix</h1>
            <canvas id="q" width="500" height="500"></canvas>
        </div>
    </body>

</html>