js实现瞄

实现鼠标跟随效果

使用JavaScript实现鼠标跟随效果通常涉及监听鼠标移动事件，并更新页面元素的位置。以下是两种常见实现方式：

基础实现（DOM元素跟随）

document.addEventListener('mousemove', (e) => {
  const follower = document.getElementById('follower');
  follower.style.left = `${e.clientX}px`;
  follower.style.top = `${e.clientY}px`;
});

平滑跟随效果（带延迟）

let posX = 0, posY = 0;
const follower = document.getElementById('follower');
const delay = 20; // 延迟系数

document.addEventListener('mousemove', (e) => {
  posX = e.clientX;
  posY = e.clientY;
});

function updateFollower() {
  const currentX = parseFloat(follower.style.left || 0);
  const currentY = parseFloat(follower.style.top || 0);

  follower.style.left = `${currentX + (posX - currentX) / delay}px`;
  follower.style.top = `${currentY + (posY - currentY) / delay}px`;

  requestAnimationFrame(updateFollower);
}

updateFollower();

实现自定义光标

如需替换默认光标为自定义图形：

document.body.style.cursor = 'none';
const customCursor = document.createElement('div');
customCursor.id = 'custom-cursor';
document.body.appendChild(customCursor);

document.addEventListener('mousemove', (e) => {
  customCursor.style.transform = `translate(${e.clientX}px, ${e.clientY}px)`;
});

对应CSS示例：

#custom-cursor {
  position: fixed;
  width: 32px;
  height: 32px;
  background: url('cursor.png') no-repeat;
  pointer-events: none;
  z-index: 9999;
}

高级效果实现

粒子跟随效果

class Particle {
  constructor() {
    this.x = 0;
    this.y = 0;
    this.size = Math.random() * 5 + 2;
    this.speedX = Math.random() * 3 - 1.5;
    this.speedY = Math.random() * 3 - 1.5;
  }

  update() {
    this.x += this.speedX;
    this.y += this.speedY;
    if (this.size > 0.2) this.size -= 0.1;
  }

  draw(ctx) {
    ctx.fillStyle = `hsl(${Math.random() * 360}, 100%, 50%)`;
    ctx.beginPath();
    ctx.arc(this.x, this.y, this.size, 0, Math.PI * 2);
    ctx.fill();
  }
}

const canvas = document.createElement('canvas');
document.body.appendChild(canvas);
const ctx = canvas.getContext('2d');
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;

let particles = [];
document.addEventListener('mousemove', (e) => {
  for (let i = 0; i < 5; i++) {
    particles.push(new Particle());
    particles[particles.length - 1].x = e.clientX;
    particles[particles.length - 1].y = e.clientY;
  }
});

function animate() {
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  for (let i = 0; i < particles.length; i++) {
    particles[i].update();
    particles[i].draw(ctx);
    if (particles[i].size <= 0.2) {
      particles.splice(i, 1);
      i--;
    }
  }
  requestAnimationFrame(animate);
}

animate();

性能优化建议

对于复杂效果，使用Canvas比操作DOM元素性能更好。避免在mousemove事件中直接进行复杂计算，可以使用防抖技术或requestAnimationFrame优化性能。

let mouseX = 0, mouseY = 0;
document.addEventListener('mousemove', (e) => {
  mouseX = e.clientX;
  mouseY = e.clientY;
});

function render() {
  // 更新逻辑放在这里
  requestAnimationFrame(render);
}

render();