小星星特效

前言

这是使用原生 JS 实现的一款鼠标经过特效，实现效果如下图

案例展示

源码

    <script>
      //鼠标经过小星星特效
      (function fairyDustCursor() {
        var possibleColors = ["#D61C59", "#E7D84B", "#1B8798"];
        var width = window.innerWidth;
        var height = window.innerHeight;
        var cursor = { x: width / 2, y: width / 2 };
        var particles = [];

        function init() {
          bindEvents();
          loop();
        }

        // Bind events that are needed
        function bindEvents() {
          document.addEventListener("mousemove", onMouseMove);
          document.addEventListener("touchmove", onTouchMove);
          document.addEventListener("touchstart", onTouchMove);

          window.addEventListener("resize", onWindowResize);
        }

        function onWindowResize(e) {
          width = window.innerWidth;
          height = window.innerHeight;
        }

        function onTouchMove(e) {
          if (e.touches.length > 0) {
            for (var i = 0; i < e.touches.length; i++) {
              addParticle(
                e.touches[i].clientX,
                e.touches[i].clientY,
                possibleColors[
                  Math.floor(Math.random() * possibleColors.length)
                ]
              );
            }
          }
        }

        function onMouseMove(e) {
          cursor.x = e.clientX;
          cursor.y = e.clientY;

          addParticle(
            cursor.x,
            cursor.y,
            possibleColors[Math.floor(Math.random() * possibleColors.length)]
          );
        }

        function addParticle(x, y, color) {
          var particle = new Particle();
          particle.init(x, y, color);
          particles.push(particle);
        }

        function updateParticles() {
          // Updated
          for (var i = 0; i < particles.length; i++) {
            particles[i].update();
          }

          // Remove dead particles
          for (var i = particles.length - 1; i >= 0; i--) {
            if (particles[i].lifeSpan < 0) {
              particles[i].die();
              particles.splice(i, 1);
            }
          }
        }

        function loop() {
          requestAnimationFrame(loop);
          updateParticles();
        }

        /**
         * Particles
         */

        function Particle() {
          this.character = "*";
          this.lifeSpan = 120; //ms
          this.initialStyles = {
            position: "fixed",
            top: "0", //必须加
            display: "block",
            pointerEvents: "none",
            "z-index": "10000000",
            fontSize: "20px",
            "will-change": "transform",
          };

          // Init, and set properties
          this.init = function (x, y, color) {
            this.velocity = {
              x: (Math.random() < 0.5 ? -1 : 1) * (Math.random() / 2),
              y: 1,
            };

            this.position = { x: x - 10, y: y - 20 };
            this.initialStyles.color = color;
            this.element = document.createElement("span");
            this.element.innerHTML = this.character;
            applyProperties(this.element, this.initialStyles);
            this.update();

            document.body.appendChild(this.element);
          };

          this.update = function () {
            this.position.x += this.velocity.x;
            this.position.y += this.velocity.y;
            this.lifeSpan--;

            this.element.style.transform =
              "translate3d(" +
              this.position.x +
              "px," +
              this.position.y +
              "px,0) scale(" +
              this.lifeSpan / 120 +
              ")";
          };

          this.die = function () {
            this.element.parentNode.removeChild(this.element);
          };
        }

        /**
         * Utils
         */

        // Applies css `properties` to an element.
        function applyProperties(target, properties) {
          for (var key in properties) {
            target.style[key] = properties[key];
          }
        }

        init();
      })();
    </script>