JS实现页面点击小球爆炸特效

效果演示

JS文件代码

function clickEffect() {
    let balls = [];
    let longPressed = false;
    let longPress;
    let multiplier = 0;
    let width, height;
    let origin;
    let normal;
    let ctx;
    const colours = ["#F73859", "#14FFEC", "#00E0FF", "#FF99FE", "#FAF15D"];
    const canvas = document.createElement("canvas");
    document.body.appendChild(canvas);
    canvas.setAttribute("style", "width: 100%; height: 100%; top: 0; left: 0; z-index: 99999; position: fixed; pointer-events: none;");
    const pointer = document.createElement("span");
    pointer.classList.add("pointer");
    document.body.appendChild(pointer);
    
    if (canvas.getContext && window.addEventListener) {
    ctx = canvas.getContext("2d");
    updateSize();
    window.addEventListener('resize', updateSize, false);
    loop();
    window.addEventListener("mousedown", function(e) {
    pushBalls(randBetween(10, 20), e.clientX, e.clientY);
    document.body.classList.add("is-pressed");
    longPress = setTimeout(function() {
    document.body.classList.add("is-longpress");
    longPressed = true;
    }, 500);
    }, false);
    window.addEventListener("mouseup", function(e) {
    clearInterval(longPress);
    if (longPressed == true) {
    document.body.classList.remove("is-longpress");
    pushBalls(randBetween(50 + Math.ceil(multiplier), 100 + Math.ceil(multiplier)), e.clientX, e.clientY);
    longPressed = false;
    }
    document.body.classList.remove("is-pressed");
    }, false);
    window.addEventListener("mousemove", function(e) {
    let x = e.clientX;
    let y = e.clientY;
    pointer.style.top = y + "px";
    pointer.style.left = x + "px";
    }, false);
    } else {
    console.log("canvas or addEventListener is unsupported!");
    }
    
    function updateSize() {
    canvas.width = window.innerWidth * 2;
    canvas.height = window.innerHeight * 2;
    canvas.style.width = window.innerWidth + 'px';
    canvas.style.height = window.innerHeight + 'px';
    ctx.scale(2, 2);
    width = (canvas.width = window.innerWidth);
    height = (canvas.height = window.innerHeight);
    origin = {
    x: width / 2,
    y: height / 2
    };
    normal = {
    x: width / 2,
    y: height / 2
    };
    }
    class Ball {
    constructor(x = origin.x, y = origin.y) {
    this.x = x;
    this.y = y;
    this.angle = Math.PI * 2 * Math.random();
    if (longPressed == true) {
    this.multiplier = randBetween(14 + multiplier, 15 + multiplier);
    } else {
    this.multiplier = randBetween(6, 12);
    }
    this.vx = (this.multiplier + Math.random() * 0.5) * Math.cos(this.angle);
    this.vy = (this.multiplier + Math.random() * 0.5) * Math.sin(this.angle);
    this.r = randBetween(8, 12) + 3 * Math.random();
    this.color = colours[Math.floor(Math.random() * colours.length)];
    }
    update() {
    this.x += this.vx - normal.x;
    this.y += this.vy - normal.y;
    normal.x = -2 / window.innerWidth * Math.sin(this.angle);
    normal.y = -2 / window.innerHeight * Math.cos(this.angle);
    this.r -= 0.3;
    this.vx *= 0.9;
    this.vy *= 0.9;
    }
    }
    
    function pushBalls(count = 1, x = origin.x, y = origin.y) {
    for (let i = 0; i < count; i++) {
    balls.push(new Ball(x, y));
    }
    }
    
    function randBetween(min, max) {
    return Math.floor(Math.random() * max) + min;
    }
    
    function loop() {
    ctx.fillStyle = "rgba(255, 255, 255, 0)";
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    for (let i = 0; i < balls.length; i++) {
    let b = balls[i];
    if (b.r < 0) continue;
    ctx.fillStyle = b.color;
    ctx.beginPath();
    ctx.arc(b.x, b.y, b.r, 0, Math.PI * 2, false);
    ctx.fill();
    b.update();
    }
    if (longPressed == true) {
    multiplier += 0.2;
    } else if (!longPressed && multiplier >= 0) {
    multiplier -= 0.4;
    }
    removeBall();
    requestAnimationFrame(loop);
    }
    
    function removeBall() {
    for (let i = 0; i < balls.length; i++) {
    let b = balls[i];
    if (b.x + b.r < 0 || b.x - b.r > width || b.y + b.r < 0 || b.y - b.r > height || b.r < 0) {
    balls.splice(i, 0.5);
    }
    }
    }
    }

使用方式

调用代码：

<script>
    clickEffect();
</script>