jquery - 如果用户向下滚动页面，第一个标题元素就会消失

Question

我开发了以下简单的 HMTL 和 CSS 代码，您也可以在 de JSFiddle here 中找到它们。 :

body {
  margin: 0;
}

.header {
  width: 80%;
  height: 10%;
  margin-left: 10%;
  position: fixed;
  top: 0;
  
  box-sizing: border-box;
  border-style: solid;
  border-width: 1px;
  background-color: yellow;
}

.sub_header_01 {
  width: 100%;
  height: 100%;
  float: left;
  text-align: center;
  
  box-sizing: border-box;
  border-style: solid;
  border-width: 1px;
  background-color: blue;   
}

.sub_header_02 {
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: space-between;
  float: left;
  
  box-sizing: border-box;
  border-style: solid;
  border-width: 1px;
  background-color: yellow;
}

.image {
  width: 30%;
  height: 100%;
  
  box-sizing: border-box;
  border-style: solid;
  border-width: 1px;
  background-color: green;
}


/* Navigation */

.navigation {
  width: 70%;
  height: 100%;
  position: relative; 
  
  box-sizing: border-box;
  border-style: solid;
  border-width: 1px;
  background-color: aqua;
}

.navigation_button {
 width: 20%;
 height: 100%;
 float: right;
 cursor: pointer;
 
 box-sizing: border-box;
 border-style: solid;
 border-width: 1px;
 background-color: fuchsia;
}

.bar1, .bar2, .bar3 {
 width: 100%;
 height: 20%;
 margin: 4% 0;
 background-color: #333; 
}


/* Content */

.content {
  width: 80%;
  margin-top: 10%;
  margin-left: 10%;
  box-sizing: border-box;
  border-style: solid;
  border-width: 1px;
  background-color: red;
}

<div class="header">

  <div class="sub_header_01">
  This is a webpage
  </div>

  <div class="sub_header_02">

    <div class="image">
    Image
    </div>	
  
    <div class="navigation">
  
      <div class="navigation_button">
      <div class="bar1"></div>
      <div class="bar2"></div>
      <div class="bar3"></div>
      </div>

    </div>
  
  </div>

</div>

<div class="content">
<p>Am no an listening depending up believing. Enough around remove to barton agreed regret in or it. Advantage mr estimable be commanded provision. Year well shot deny shew come now had. Shall downs stand marry taken his for out. Do related mr account brandon an up. Wrong for never ready ham these witty him. Our compass see age uncivil matters weather forbade her minutes. Ready how but truth son new under. Breakfast procuring nay end happiness allowance assurance frankness. Met simplicity nor difficulty unreserved who. Entreaties mr conviction dissimilar me astonished estimating cultivated. On no applauded exquisite my additions. Pronounce add boy estimable nay suspected. You sudden nay elinor thirty esteem temper. Quiet leave shy you gay off asked large style. Betrayed cheerful declared end and. Questions we additions is extremely incommode. Next half add call them eat face. Age lived smile six defer bed their few. Had admitting concluded too behaviour him she. Of death to or to being other. Received shutters expenses ye he pleasant. Drift as blind above at up. No up simple county stairs do should praise as. Drawings sir gay together landlord had law smallest. Formerly welcomed attended declared met say unlocked. Jennings outlived no dwelling denoting in peculiar as he believed. Behaviour excellent middleton be as it curiosity departure ourselves. On then sake home is am leaf. Of suspicion do departure at extremely he believing. Do know said mind do rent they oh hope of. General enquire picture letters garrets on offices of no on. Say one hearing between excited evening all inhabit thought you. Style begin mr heard by in music tried do. To unreserved projection no introduced invitation. Was justice improve age article between. No projection as up preference reasonably delightful celebrated. Preserved and abilities assurance tolerably breakfast use saw. And painted letters forming far village elderly compact. Her rest west each spot his and you knew. Estate gay wooded depart six far her. Of we be have it lose gate bred. Do separate removing or expenses in. Had covered but evident chapter matters anxious. Received overcame oh sensible so at an. Formed do change merely to county it. Am separate contempt domestic to to oh. On relation my so addition branched. Put hearing cottage she norland letters equally prepare too. Replied exposed savings he no viewing as up. Soon body add him hill. No father living really people estate if. Mistake do produce beloved demesne if am pursuit. Cause dried no solid no an small so still widen. Ten weather evident smiling bed against she examine its. Rendered far opinions two yet moderate sex striking. Sufficient motionless compliment by stimulated assistance at. Convinced resolving extensive agreeable in it on as remainder. Cordially say affection met who propriety him. Are man she towards private weather pleased. In more part he lose need so want rank no. At bringing or he sensible pleasure. Prevent he parlors do waiting be females an message society. Situation admitting promotion at or to perceived be. Mr acuteness we as estimable enjoyment up. An held late as felt know. Learn do allow solid to grave. Middleton suspicion age her attention. Chiefly several bed its wishing. Is so moments on chamber pressed to. Doubtful yet way properly answered humanity its desirous. Minuter believe service arrived civilly add all. Acuteness allowance an at eagerness favourite in extensive exquisite ye. Remain valley who mrs uneasy remove wooded him you. Her questions favourite him concealed. We to wife face took he. The taste begin early old why since dried can first. Prepared as or humoured formerly. Evil mrs true get post. Express village evening prudent my as ye hundred forming. Thoughts she why not directly reserved packages you. Winter an silent favour of am tended mutual. </p>

如您所见，我有一个由两个子标题组成的标题。 .sub-header_01 显示网站的标题，.sub_header_02 在左侧提供 .image 和 。导航位于右侧。

到目前为止，所有这些都运行良好。

---

现在，我的目标是在用户向下滚动内容后使 .sub_header_01 消失。 .sub_header_02 应保持在 .position:fixed 位置，而 .sub_header_01 在页面向下滚动时应消失强>。一旦用户向上滚动，.sub_header_01 就会再次出现。

您知道我需要在代码中更改哪些内容才能使其正常工作吗？

Answer 1

(function(){
var position = 0; 

  // should start at 0

  $(window).scroll(function() {
      var scroll = $(window).scrollTop();
      if(scroll > position) {
          $('.sub_header_01').hide();
      } else {
          $('.sub_header_01').show();
      }
      position = scroll;
  });
})()

body {
  margin: 0;
}

.header {
  width: 80%;
  height: 10%;
  margin-left: 10%;
  position: fixed;
  top: 0;
  
  box-sizing: border-box;
  border-style: solid;
  border-width: 1px;
  background-color: yellow;
}

.sub_header_01 {
  width: 100%;
  height: 100%;
  float: left;
  text-align: center;
  
  box-sizing: border-box;
  border-style: solid;
  border-width: 1px;
  background-color: blue;   
}

.sub_header_02 {
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: space-between;
  float: left;
  
  box-sizing: border-box;
  border-style: solid;
  border-width: 1px;
  background-color: yellow;
}

.image {
  width: 30%;
  height: 100%;
  
  box-sizing: border-box;
  border-style: solid;
  border-width: 1px;
  background-color: green;
}


/* Navigation */

.navigation {
  width: 70%;
  height: 100%;
  position: relative; 
  
  box-sizing: border-box;
  border-style: solid;
  border-width: 1px;
  background-color: aqua;
}

.navigation_button {
 width: 20%;
 height: 100%;
 float: right;
 cursor: pointer;
 
 box-sizing: border-box;
 border-style: solid;
 border-width: 1px;
 background-color: fuchsia;
}

.bar1, .bar2, .bar3 {
 width: 100%;
 height: 20%;
 margin: 4% 0;
 background-color: #333; 
}


/* Content */

.content {
  width: 80%;
  margin-top: 10%;
  margin-left: 10%;
  box-sizing: border-box;
  border-style: solid;
  border-width: 1px;
  background-color: red;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.0.0/jquery.min.js"></script>
<div class="header">

  <div class="sub_header_01">
  This is a webpage
  </div>

  <div class="sub_header_02">

    <div class="image">
    Image
    </div>	
  
    <div class="navigation">
  
      <div class="navigation_button">
      <div class="bar1"></div>
      <div class="bar2"></div>
      <div class="bar3"></div>
      </div>

    </div>
  
  </div>

</div>

<div class="content">
<p>Am no an listening depending up believing. Enough around remove to barton agreed regret in or it. Advantage mr estimable be commanded provision. Year well shot deny shew come now had. Shall downs stand marry taken his for out. Do related mr account brandon an up. Wrong for never ready ham these witty him. Our compass see age uncivil matters weather forbade her minutes. Ready how but truth son new under. Breakfast procuring nay end happiness allowance assurance frankness. Met simplicity nor difficulty unreserved who. Entreaties mr conviction dissimilar me astonished estimating cultivated. On no applauded exquisite my additions. Pronounce add boy estimable nay suspected. You sudden nay elinor thirty esteem temper. Quiet leave shy you gay off asked large style. Betrayed cheerful declared end and. Questions we additions is extremely incommode. Next half add call them eat face. Age lived smile six defer bed their few. Had admitting concluded too behaviour him she. Of death to or to being other. Received shutters expenses ye he pleasant. Drift as blind above at up. No up simple county stairs do should praise as. Drawings sir gay together landlord had law smallest. Formerly welcomed attended declared met say unlocked. Jennings outlived no dwelling denoting in peculiar as he believed. Behaviour excellent middleton be as it curiosity departure ourselves. On then sake home is am leaf. Of suspicion do departure at extremely he believing. Do know said mind do rent they oh hope of. General enquire picture letters garrets on offices of no on. Say one hearing between excited evening all inhabit thought you. Style begin mr heard by in music tried do. To unreserved projection no introduced invitation. Was justice improve age article between. No projection as up preference reasonably delightful celebrated. Preserved and abilities assurance tolerably breakfast use saw. And painted letters forming far village elderly compact. Her rest west each spot his and you knew. Estate gay wooded depart six far her. Of we be have it lose gate bred. Do separate removing or expenses in. Had covered but evident chapter matters anxious. Received overcame oh sensible so at an. Formed do change merely to county it. Am separate contempt domestic to to oh. On relation my so addition branched. Put hearing cottage she norland letters equally prepare too. Replied exposed savings he no viewing as up. Soon body add him hill. No father living really people estate if. Mistake do produce beloved demesne if am pursuit. Cause dried no solid no an small so still widen. Ten weather evident smiling bed against she examine its. Rendered far opinions two yet moderate sex striking. Sufficient motionless compliment by stimulated assistance at. Convinced resolving extensive agreeable in it on as remainder. Cordially say affection met who propriety him. Are man she towards private weather pleased. In more part he lose need so want rank no. At bringing or he sensible pleasure. Prevent he parlors do waiting be females an message society. Situation admitting promotion at or to perceived be. Mr acuteness we as estimable enjoyment up. An held late as felt know. Learn do allow solid to grave. Middleton suspicion age her attention. Chiefly several bed its wishing. Is so moments on chamber pressed to. Doubtful yet way properly answered humanity its desirous. Minuter believe service arrived civilly add all. Acuteness allowance an at eagerness favourite in extensive exquisite ye. Remain valley who mrs uneasy remove wooded him you. Her questions favourite him concealed. We to wife face took he. The taste begin early old why since dried can first. Prepared as or humoured formerly. Evil mrs true get post. Express village evening prudent my as ye hundred forming. Thoughts she why not directly reserved packages you. Winter an silent favour of am tended mutual. </p>