vue實現吸頂的效果

export default {
  name: "nav-bar",
  data() {
    return {
      isFixed: false, //當滾動條高度大於152時是否定位
      scrollHeight: 152
    };
  },
  mounted() {
    window.addEventListener("scroll", this.initHeight);
  },
  methods: {
    // 實現吸頂效果，判斷滾動條距離頂部的距離
    initHeight() {
      let scrollTop =
        window.pageYOffset ||
        document.documentElement.scrollTop ||
        document.body.scrollTop;
      this.isFixed = scrollTop > this.scrollHeight ? true : false;
    }
  },
  destroyed() {
    window.removeEventListener("scroll", this.initHeight, false);
  }
};