技術標籤：jsjavascriptvue.jshtml

• 今天博主遇到這個問題這首頁寫了這個滾動函式（這是原版的）但是從這個頁面跳轉其他頁面後會報錯

 /** 獲取DOM元素 **/
    getList() {
      let that = this
      let ul1 = document.getElementById('comment1')
      let ul2 = document.getElementById('comment2')
      let ulbox = document.getElementById('review_box')
      let speed =
 
 30
      ulbox.scrollTop = 0
      ul2.innerHTML = ul1.innerHTML
      ulbox.onmouseover = function() {
        clearInterval(myScroll)
      }
      ulbox.onmouseout = function() {
        myScroll = setInterval(that.rollStart, speed)
      }
      var myScroll = setInterval(that.rollStart, speed)
    }
 
,
    // 開始滾動函式
    rollStart() {
      // 上面宣告的DOM物件為區域性物件需要再次宣告
      var ul1 = document.getElementById('comment1')
      var ul2 = document.getElementById('comment2')
      var ulbox = document.getElementById('review_box')
      // console.log(ulbox.scrollTop)
      // console.log(ul1.scrollHeight)
       if
 
 (ulbox.scrollTop >= ul1.scrollHeight) {
          ulbox.scrollTop = 0
        } else {
          ulbox.scrollTop++
        }
    }

後來博主打斷點後發現 ul1 和 ulbox都是null 我懷疑是vue還沒有把他們從DOM樹了給解除安裝下來。所以改動了一下

 /** 獲取DOM元素 **/
    getList() {
      let that = this
      let ul1 = document.getElementById('comment1')
      let ul2 = document.getElementById('comment2')
      let ulbox = document.getElementById('review_box')
      let speed = 30
      ulbox.scrollTop = 0
      ul2.innerHTML = ul1.innerHTML
      ulbox.onmouseover = function() {
        clearInterval(myScroll)
      }
      ulbox.onmouseout = function() {
        myScroll = setInterval(that.rollStart, speed)
      }
      var myScroll = setInterval(that.rollStart, speed)
    },
    // 開始滾動函式
    rollStart() {
      // 上面宣告的DOM物件為區域性物件需要再次宣告
      var ul1 = document.getElementById('comment1')
      var ul2 = document.getElementById('comment2')
      var ulbox = document.getElementById('review_box')
      // console.log(ulbox.scrollTop)
      // console.log(ul1.scrollHeight)
      if (ulbox !== null && ul1 !== null) {
        if (ulbox.scrollTop >= ul1.scrollHeight) {
          ulbox.scrollTop = 0
        } else {
          ulbox.scrollTop++
        }
      }
    }

求大神指點一二