javascript - 为什么搜索栏会改变标题的位置？

Question

我正在创建一个带有搜索栏和标题的 HTML/CSS/JS 项目。当搜索栏被激活/停用（点击）时，它会改变我的标题的位置。如何解决此问题并将标题保持在同一位置？非常感谢！

function myFunction() {
    var input, filter, ul, li, a, i, txtValue;
    input = document.getElementById("myInput");
    filter = input.value.toUpperCase();
    ul = document.getElementById("myUL");
    li = ul.getElementsByTagName("li");
    for (i = 0; i < li.length; i++) {
        a = li[i].getElementsByTagName("a")[0];
        txtValue = a.textContent || a.innerText;
        if (txtValue.toUpperCase().indexOf(filter) > -1 && filter != "") {//change here
            li[i].style.display = "";
            li[i].style.visibility = "visible";//change here
        } else {
            li[i].style.display = "none";
        }
    }
}

body {
   background-image: url('paperforrite-removebg-preview.png');
}
#myInput {
  background-image: url('/css/searchicon.png');
  background-position: 10px 12px;
  background-repeat: no-repeat;
  width: 500px;
  font-size: 16px;
  padding: 12px 20px 12px 40px;
  border: 1px solid #ddd;
  margin-bottom: 12px;
  border-radius: 4px;
}

#myUL {
  list-style-type: none;
  padding: 0;
  margin: 0;
  width: 558px;
}

#myUL li a {
  border: 1px solid #ddd;
  margin-top: -1px;
  background-color: #f6f6f6;
  padding: 12px;
  text-decoration: none;
  font-size: 18px;
  color: black;
  display: block;
}

#myUL li a:hover:not(.header) {
  background-color: #eee;
}

<input type="text" id="myInput" onkeyup="myFunction()" placeholder="Search for names.." style="font-family: 'Poppins', sans-serif;">
<ul id="myUL" style="visibility: hidden">
  <li><a href="#">Adele</a></li>
  <li><a href="#">Agnes</a></li>

  <li><a href="#">Billy</a></li>
  <li><a href="#">Bob</a></li>

  <li><a href="#">Calvin</a></li>
  <li><a href="#">Christina</a></li>
  <li><a href="#">Cindy</a></li>
</ul>
<br>
<br>
<h1><center style="font-family: 'Poppins', sans-serif; font-size: 100px; color: #000000;">Some text here</center></h1>
<br>
<br>
<h2><center style="font-family: 'Poppins', sans-serif; font-size: 20px; color: #000000;">Some text here</center></h2>

标签： javascripthtmlcss

Answer 1

只需添加 position: absolute;到#myUl css 标签，如下所示。

您当前的 ul 标签是流程的一部分，因此将所有内容都向下推。

起初，它会将所有内容向下推，因为它具有visibility: hidden，这会以其高度/宽度呈现 ul。

然后，当您在搜索栏中键入内容时，您的 javascript 会启动，这反过来会隐藏带有 display: none 的块，删除其块属性并且不使其呈现高度/宽度。

如果您希望保留块行为（下推标题），只需在 ul html 中切换visibility: hidden到。display: none

function myFunction() {
    var input, filter, ul, li, a, i, txtValue;
    input = document.getElementById("myInput");
    filter = input.value.toUpperCase();
    ul = document.getElementById("myUL");
    li = ul.getElementsByTagName("li");
    for (i = 0; i < li.length; i++) {
        a = li[i].getElementsByTagName("a")[0];
        txtValue = a.textContent || a.innerText;
        if (txtValue.toUpperCase().indexOf(filter) > -1 && filter != "") {//change here
            li[i].style.display = "";
            li[i].style.visibility = "visible";//change here
        } else {
            li[i].style.display = "none";
        }
    }
}

body {
   background-image: url('paperforrite-removebg-preview.png');
}
#myInput {
  background-image: url('/css/searchicon.png');
  background-position: 10px 12px;
  background-repeat: no-repeat;
  width: 500px;
  font-size: 16px;
  padding: 12px 20px 12px 40px;
  border: 1px solid #ddd;
  margin-bottom: 12px;
  border-radius: 4px;
}

#myUL {
  list-style-type: none;
  padding: 0;
  margin: 0;
  width: 558px;
  position: absolute;
}

#myUL li a {
  border: 1px solid #ddd;
  margin-top: -1px;
  background-color: #f6f6f6;
  padding: 12px;
  text-decoration: none;
  font-size: 18px;
  color: black;
  display: block;
}

#myUL li a:hover:not(.header) {
  background-color: #eee;
}

<input type="text" id="myInput" onkeyup="myFunction()" placeholder="Search for names.." style="font-family: 'Poppins', sans-serif;">
<ul id="myUL" style="visibility: hidden">
  <li><a href="#">Adele</a></li>
  <li><a href="#">Agnes</a></li>

  <li><a href="#">Billy</a></li>
  <li><a href="#">Bob</a></li>

  <li><a href="#">Calvin</a></li>
  <li><a href="#">Christina</a></li>
  <li><a href="#">Cindy</a></li>
</ul>
<br>
<br>
<h1><center style="font-family: 'Poppins', sans-serif; font-size: 100px; color: #000000;">Some text here</center></h1>
<br>
<br>
<h2><center style="font-family: 'Poppins', sans-serif; font-size: 20px; color: #000000;">Some text here</center></h2>