<!-- tab切換star -->
   <ul class="tab-list" :class="{fixTitle:whether}">
    <li @click="curId=0" :class="{'cur':curId===0}">產(chǎn)品特點(diǎn)</li>
    <li @click="curId=1" :class="{'cur':curId===1}">投保須知</li>
    <li @click="curId=2" :class="{'cur':curId===2}">理賠流程</li>
   </ul>
  <!-- 切換內(nèi)容star -->

<div class="tab-con">
 <div v-show="curId===0">
    第一部分內(nèi)容
  </div>
 <div v-show="curId===1">
    第二部分內(nèi)容
  </div>
 <div v-show="curId===2">
    第三部分內(nèi)容
  </div>
</div>

data(){
  return:{
    whether:false,
    curId:0
  }
}

  handleScroll() {
   var scrollTop =
    window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop;
   // console.log(scrollTop)
   if(scrollTop>329){
    this.whether = true;
   }else{
    this.whether = false;
   }
  },

<template>
  <div class="tab__main" :style="prop.box_style ? prop.box_style : ''">
    <div class="tab__div">
      <ul class="tab__list" :style="prop.attr.tab_style ? prop.attr.tab_style : ''">
        <li class="tab__item" v-for="(tabs, index) in prop.attr.tab_content" :key="tabs.tab_menu" @click="onClickTabs(index)"
        >
          <span :style="tabStyle(index)">{{ tabs.tab_menu }}</span>
        </li>
      </ul>
      <div class="active__line" :style="prop.attr.cur_slide_style ? prop.attr.cur_slide_style : ''"></div>
    </div>
  </div>
</template>

.tab__div {
  width: 100%;
  height: 102px;
  position: relative;
  padding-top: 36px;
  background-color: #fff;
  .tab__list {
    display: flex;
    .tab__item {
      flex: 1;
      font-size: 32px;
    }
    .tab__item-current {
      font-weight: 700;
    }
  }
  .active__line {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 187.5px;
    height: 5px;
    background-color: #4B8FFB;
    transition: all 300ms;
  }
}

export default {
  name: 'TabModule',
  props: {
    prop: {
      type: Object
    }
  },
  data () {
    return {
      scrolltop: null,
      dom: null,
      domobj: {} // 各個(gè)dom的頁面位置
    }
  },
  computed: {
    tabStyle () {
      return function (params) {
        return this.prop.attr.tab_content[params].tab_style || ''
      }
    }
  },
  mounted () {
    this.onWatchScroll()
    // 這里首次進(jìn)入頁面當(dāng)前選中項(xiàng)為第一個(gè)
    document.querySelectorAll('.tab__item')[0].style = this.prop.attr.cur_tab_style ? this.prop.attr.cur_tab_style : ''
  },
  methods: {
    // 獲取各個(gè)dom的頁面位置
    getDomsObj () {
      this.domobj.dom1 = document.querySelectorAll(`#${this.prop.attr.tab_content[0].anchor_point}`)[0].offsetTop
      this.domobj.dom2 = document.querySelectorAll(`#${this.prop.attr.tab_content[1].anchor_point}`)[0].offsetTop
      this.domobj.dom3 = document.querySelectorAll(`#${this.prop.attr.tab_content[2].anchor_point}`)[0].offsetTop
      this.domobj.dom4 = document.querySelectorAll(`#${this.prop.attr.tab_content[3].anchor_point}`)[0].offsetTop
    },
    // 計(jì)算當(dāng)前選中滑動(dòng)塊兒的滑動(dòng)距離和當(dāng)前選中項(xiàng)
    computerSlide (val) {
      let tablist = document.querySelectorAll('.tab__item')
      for (let i = 0; i < tablist.length; i++) {
        tablist[i].style = ''
      }
      document.querySelector('.active__line').style.transform = `translateX(${(val * document.querySelector('.active__line').offsetWidth)}px)`
      // 當(dāng)前選中的tab_item的狀態(tài)
      tablist[val].style = this.prop.attr.cur_tab_style ? this.prop.attr.cur_tab_style : ''
    },
    onClickTabs (index) {
      this.computerSlide(index)
      // 計(jì)算點(diǎn)擊后滑動(dòng)到DOM的位置
      this.dom = document.querySelectorAll(`#${this.prop.attr.tab_content[index].anchor_point}`)[0].offsetTop
      let tabbox = document.querySelectorAll('.tab__div')[0]
      if (index === 0) {
        if (tabbox.style.position === 'relative') {
          window.scrollTo(0, this.dom - tabbox.clientHeight)
          return
        }
        window.scrollTo(0, this.dom)
        return
      }
      if (index === 3) {
        window.scrollTo(0, this.dom)
        return
      }
      if (tabbox.style.position === 'relative') {
        window.scrollTo(0, this.dom - (tabbox.clientHeight * 2))
      } else {
        window.scrollTo(0, this.dom - tabbox.clientHeight)
      }
    },
    onWatchScroll () {
      let tabmain = document.querySelectorAll('.tab__main')[0]
      let tabdiv = document.querySelectorAll('.tab__div')[0]
      tabdiv.style.top = 0
      window.onscroll = () => {
        // 由于在created()或者mounted()鉤子函數(shù)中獲取到的dom位置不對(duì)，在滑動(dòng)中獲取dom的頁面位置
        this.getDomsObj()
        this.scrolltop = document.documentElement.scrollTop || document.body.scrollTop || window.pageYOffset
        // 滑動(dòng)根據(jù)滾動(dòng)距離來計(jì)算當(dāng)前可是區(qū)域的選中項(xiàng)
        this.onScrollPage()
        // 自定義吸頂效果
        if (this.scrolltop > tabmain.offsetTop) {
          tabdiv.style.position = 'fixed'
          tabdiv.style['z-index'] = 99
        } else {
          tabdiv.style.position = 'relative'
          tabdiv.style['z-index'] = 0
        }
      }
    },
    onScrollPage () {
      let tab = document.querySelectorAll('.tab__div')[0]
      if (this.scrolltop > this.domobj.dom1 && this.scrolltop < (this.domobj.dom2 - tab.offsetHeight * 2)) {
        this.computerSlide(0)
      } else if (this.scrolltop > (this.domobj.dom2 - tab.offsetHeight * 2) && this.scrolltop < this.domobj.dom3 - tab.offsetHeight * 2) {
        this.computerSlide(1)
      } else if (this.scrolltop > (this.domobj.dom3 - tab.offsetHeight * 2) && this.scrolltop < (this.domobj.dom3 + tab.offsetHeight * 2)) {
        this.computerSlide(2)
      } else if (this.scrolltop > (this.domobj.dom4 - tab.offsetHeight * 10) && this.scrolltop < this.domobj.dom4) {
        this.computerSlide(3)
      }
    }
  }
}

<template>
  <div>
    <div class="div__header"></div>
    <tab-module :prop="tabattributes"></tab-module>
    <div :id="tabattributes.attr.tab_content[index].anchor_point" class="div__item" v-for="(item, index) in fordiv" :key="item">{{ item }}</div>
    <div class="div__footer">我是有底線的</div>
  </div>
</template>

import TabModule from '../../components/TabModule.vue'
export default {
  components: {
    TabModule
  },
  data () {
    return {
      tabattributes: {
        box_style: "margin-top: 10px;",         
        attr: {      
          cur_tab_style: "font-weight: 700;", 
          cur_slide_style: "",
          tab_content: [{
            tab_menu: "控件1",       
            anchor_point: "DomPoint1",
            tab_style: "" 
          }, {
            tab_menu: "控件2",       
            anchor_point: "DomPoint2",  
            tab_style: "" 
          }, {
            tab_menu: "控件3",       
            anchor_point: "DomPoint3",  
            tab_style: "" 
          }, {
            tab_menu: "控件4",       
            anchor_point: "DomPoint4", 
            tab_style: "" 
          }]
        }
      },
      fordiv: ['頁面控件1', '頁面控件2', '頁面控件3', '頁面控件4']
    }
  }
}

<style lang="less" scoped>
.div__header {
  width: 100%;
  height: 200px;
  background-color: #909;
}
.div__item {
  width: 100%;
  height: 400px;
  background-color: rgb(78, 215, 224);
  text-align: center;
  font-size: 26px;
}
.div__footer {
  width: 100%;
  height: 200px;
  background-color: #090;
}
</style>