有趣的JS

<script type="text/javascript">
onload = function() {
    var click_cnt = 0;
    var $html = document.getElementsByTagName("html")[0];
    var $body = document.getElementsByTagName("body")[0];

    var canvas = document.createElement("canvas");
    var ctx = canvas.getContext("2d");

    resize();
    window.onresize = resize;

    function resize() {
        canvas.width = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth;
        canvas.height = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight;
    }

    var RAF = (function() {
        return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame ||
        function(callback) {
            window.setTimeout(callback, 1000 / 60);
        };
    })();

    // 鼠标活动时，获取鼠标坐标
    var warea = {
        x: null,
        y: null,
        max: 20000
    };
    window.onmousemove = function(e) {
        e = e || window.event;

        warea.x = e.clientX;
        warea.y = e.clientY;
    };
    window.onmouseout = function(e) {
        warea.x = null;
        warea.y = null;
    };

    // 添加粒子
    // x，y为粒子坐标，xa, ya为粒子xy轴加速度，max为连线的最大距离
    var dots = [];
    for (var i = 0; i < 300; i++) {
        var x = Math.random() * canvas.width;
        var y = Math.random() * canvas.height;
        var xa = Math.random() * 2 - 1;
        var ya = Math.random() * 2 - 1;

        dots.push({
            x: x,
            y: y,
            xa: xa,
            ya: ya,
            max: 6000
        })
    }

    // 延迟100秒开始执行动画，如果立即执行有时位置计算会出错
    setTimeout(function() {
        animate();
    },
    100);

    // 每一帧循环的逻辑
    function animate() {
        ctx.clearRect(0, 0, canvas.width, canvas.height);

        // 将鼠标坐标添加进去，产生一个用于比对距离的点数组
        var ndots = [warea].concat(dots);

        dots.forEach(function(dot) {

            // 粒子位移
            dot.x += dot.xa;
            dot.y += dot.ya;

            // 遇到边界将加速度反向
            dot.xa *= (dot.x > canvas.width || dot.x < 0) ? -1 : 1;
            dot.ya *= (dot.y > canvas.height || dot.y < 0) ? -1 : 1;

            // 绘制点
            ctx.fillRect(dot.x - 0.5, dot.y - 0.5, 1, 1);

            // 循环比对粒子间的距离
            for (var i = 0; i < ndots.length; i++) {
                var d2 = ndots[i];

                if (dot === d2 || d2.x === null || d2.y === null) continue;

                var xc = dot.x - d2.x;
                var yc = dot.y - d2.y;

                // 两个粒子之间的距离
                var dis = xc * xc + yc * yc;

                // 距离比
                var ratio;

                // 如果两个粒子之间的距离小于粒子对象的max值，则在两个粒子间画线
                if (dis < d2.max) {

                    // 如果是鼠标，则让粒子向鼠标的位置移动
                    if (d2 === warea && dis > (d2.max / 2)) {
                        dot.x -= xc * 0.03;
                        dot.y -= yc * 0.03;
                    }

                    // 计算距离比
                    ratio = (d2.max - dis) / d2.max;

                    // 画线
                    ctx.beginPath();
                    ctx.lineWidth = ratio / 2;
                    ctx.strokeStyle = 'rgba(137,129,150,' + (ratio + 0.2) + ')';
                    ctx.moveTo(dot.x, dot.y);
                    ctx.lineTo(d2.x, d2.y);
                    ctx.stroke();
                }
            }

            // 将已经计算过的粒子从数组中删除
            ndots.splice(ndots.indexOf(dot), 1);
        });

        RAF(animate);

    }
    $body.appendChild(canvas);

    $html.onclick = function(e) {
        var $elem = document.createElement("h1");
        // $elem.style.color = "#a7ef1e";
        $elem.style.color = getRandomColor(); // 获取随机颜色
        $elem.style.zIndex = 9999;
        $elem.style.position = "absolute";
        $elem.style.select = "none";
        var x = e.pageX;
        var y = e.pageY;
        $elem.style.left = (x - 10) + "px";
        $elem.style.top = (y - 20) + "px";
        clearInterval(anim);
        click_cnt++;
        if (click_cnt % 12 == 0) {
            $elem.innerText = "友善";
        } else if (click_cnt % 11 == 0) {
            $elem.innerText = "诚信";
        } else if (click_cnt % 10 == 0) {
            $elem.innerText = "敬业";
        } else if (click_cnt % 9 == 0) {
            $elem.innerText = "爱国";
        } else if (click_cnt % 8 == 0) {
            $elem.innerText = "法治";
        } else if (click_cnt % 7 == 0) {
            $elem.innerText = "公正";
        } else if (click_cnt % 6 == 0) {
            $elem.innerText = "平等";
        } else if (click_cnt % 5 == 0) {
            $elem.innerText = "自由";
        } else if (click_cnt % 4 == 0) {
            $elem.innerText = "和谐";
        } else if (click_cnt % 3 == 0) {
            $elem.innerText = "文明";
        } else if (click_cnt % 2 == 0) {
            $elem.innerText = "民主";
        } else if (click_cnt % 1 == 0) {
            $elem.innerText = "富强";
        }

        $elem.style.fontSize = Math.random() * 10 + 10 + "px";
        var increase = 0;
        var anim;
        setTimeout(function() {
            anim = setInterval(function() {
                if (++increase == 150) {
                    clearInterval(anim);
                    $body.removeChild($elem);
                }
                $elem.style.top = y - 20 - increase + "px";
                $elem.style.opacity = (150 - increase) / 120;
            },
            8);
        },
        70);
        $body.appendChild($elem);
    };
};

var getRandomColor = function() {
    return "rgb(" + Math.round(Math.random() * 255) + "," + Math.round(Math.random() * 255) + ',' + Math.round(Math.random() * 10) + ')';
}
</script>

有趣的JS

原文：https://www.cnblogs.com/eternityz/p/12271949.html