javascript - 将 JQuery 代码转换为 "Vanilla"JavaScript

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我正在尝试提升我的 JS 知识，因此我正在尝试将 JQuery 代码转换为 JavaScript。在此我不知道在哪里调用 x function(){which is in comment}。想要将工具提示添加到 JavaScript 而不是 JQuery。我尽力将 JQuery 代码转换为“vanilla”JS，但犯了一些错误。你能告诉我我哪里错了吗？

var persons = [{
  firstname: "Malcom",
  lastname: "Reynolds",
  id: 1
}, {
  firstname: "Kaylee",
  lastname: "Frye",
  id: 2
}, {
  firstname: "Jayne",
  lastname: "Cobb",
  id: 3
}, {
  firstname: "Mal",
  lastname: "Rlds",
  id: 4
}, {
  firstname: "ylee",
  lastname: "ye",
  id: 5
}, {
  firstname: "yne",
  lastname: "Cb",
  id: 6
}, {
  firstname: "Mal",
  lastname: "Rolds",
  id: 7
}, {
  firstname: "lee",
  lastname: "Fryedwwwwd",
  id: 8
}, {
  firstname: "Jay",
  lastname: "bdwe",
  id: 9
}, {
  firstname: "Maljh",
  lastname: "Rolds",
  id: 10
}, {
  firstname: "ljyyu",
  lastname: "jhjFryed",
  id: 11
}, {
  firstname: "ryJay",
  lastname: "jkmCdwe",
  id: 12
}, {
  firstname: "yuryMal",
  lastname: "jhkhRolds",
  id: 13
}, {
  firstname: "rtulee",
  lastname: "Frwwd",
  id: 14
}, {
  firstname: "ryuyJay",
  lastname: "Cryyobbdwe",
  id: 15
}];

var start = 1;
var size = 5;
var current = 0;

function getFullName(item, index) {
  return "<li>" + item.firstname + "<span class='tool-tip'>" + item.lastname + "</span> " + item.id + "</li>";
}

var getFullNameForHighlighting = function(searchText) {
    return function(item, index) {
       var index = item.firstname.toUpperCase().indexOf(searchText.toUpperCase())+searchText.length;
       console.log(index)
           return "<li>" + "<span class='highlight'>"+searchText + "</span>" +item.firstname.substring(index) + "<span class='tool-tip'>" + item.lastname + "</span> " + item.id + "</li>";
    }
};

function myFunction1(){
  current = size;
  document.getElementById("myUL").innerHTML = persons.map(getFullName).slice(start, current).join('');
}

function myFunction() {
  current = size;
  var input, filter, ul, li, a, i, count = 0;
  input = document.getElementById("myInput");
  filter = input.value.toUpperCase();

  var longWords = persons.filter(function(person) {

    return person.firstname.toUpperCase().indexOf(filter) > -1
  });
  var message = "Result:" + longWords.length + " words containing '" + input.value;
  document.getElementById("demo").innerHTML = message;

  ul = document.getElementById("myUL");
  varInnerHtmlText = longWords.map(getFullNameForHighlighting(filter));
  ul.innerHTML = varInnerHtmlText;
 
  highlight();
}

function highlight() {

  var inputText, filter1, innerHTML, index;
  inputText = document.getElementById("myInput");
  console.log(inputText);
  filter1 = inputText.value.toUpperCase();
  console.log(filter1);
  innerHTML1 = inputText.innerHTML;
  var ul = document.getElementById("myUL");
  console.log(innerHTML1);
  index = innerHTML1.indexOf(filter1);
  
  if (index >= 0) {
    innerHTML1 = innerHTML1.substring(0, index) + "<span class='highlight'>" + innerHTML1.substring(index, index + filter1.length) + "</span>" + innerHTML1.substring(index + filter1.length);
    filter1.innerHTML = innerHTML1;
  }
}
var x = 0;
function myFunction3(e) {
  console.log(e);
  document.getElementById("demo").innerHTML = ++x; 
}

* {
  box-sizing: border-box;
}

#myInput {
  width: 50%;
  font-size: 14px;
  padding: 8px 10px 8px 5px;
  border: 1px solid #ddd;
  margin-bottom: 12px;
  margin-top: 20px;
}

#clear {
  margin-left: 20px;
  margin-top: 40px;
  font-size: 14px;
  margin-right: 50px;
  padding: 4px 4px 4px 4px;
}

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

#myUL li a {
  border: 1px solid #ddd;
  margin-top: -1px;
  /* Prevent double borders */
  background-color: #f6f6f6;
  padding: 8px;
  text-decoration: none;
  font-size: 16px;
  color: black;
  display: block;
  width: 100%;
}

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

body {
  margin: 0;
}

.column {
  float: left;
  margin-top: 50px;
  padding: 10px;
  height: 550px;
}

.left {
  width: 20%;
}

.right {
  width: 60%;
}

.row:after {
  content: "";
  display: table;
  clear: both;
}

ul.demo {
  display: inline-block;
  border-bottom: 1px dotted black;
}

ul.demo li {
  position: right;
}

.tool-tip {
  display: none;
  width: 100px;
  background-color: white;
  color: #fff;
  text-align: center;
  border-radius: 2px;
  position: absolute;
  z-index: 1;
  color: black;
}

.highlight {
  font-weight: bold;
  color: black;
}

li em {
  background: #ff6;
  font-weight: bold;
  font-style: normal;
}

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="jquery.jscroll.js"></script>
<script src="two.js"></script>



<body onload="myFunction1()">
  <br>
  <br>

  <div class="row">
    <div class="column left" style="background-color:White;"></div>

    <div class="column right" style="background-color:#bbb;">
      <form id="myForm" onsubmit='return onSubmit(this)'>

        Find:
        <input type="text" class="demo1" id="myInput" align="center" onkeyup="myFunction()" placeholder="Search here...">

        <button id="clear" onclick="document.getElementById('myInput').value = ''"> Clear </button>

      </form>
      <br>
      <ul id="demo">
        15 words total
      </ul>
      <br>
      <div onscroll="myFunction3(this)" style="width:100%;height:250px;overflow:scroll;padding:5px;color:#714D03;scrollbar-base-color:#DEBB07;">

        <ul id="myUL" class="demo">

        </ul>
      </div>
       <p><span id="demo"></span></p> 
    </div>
  </div>
  <script>
    $('#myUL').on("mouseenter", "li", function() {
      $(this).find("span").show();
    })

    $('#myUL').on("mouseout", "li", function() {
      $(this).find("span").hide();
    })

  </script>

  <script>
//   function x()
//   {
//       var ul = document.getElementById("myUL").getElementsByTagName('li');
//       console.log(ul);

//       ul.addEventListener('mouseenter', function(e) {
//    if ( e.target.matchesSelector('myUL li') ) {
//         return "<li>" + item.firstname + "<span class='tool-tip'>" + item.lastname + "</span> " + item.id + "</li>";
//    }
// }, false);

//       ul.addEventListener('mouseout', function(e) {
//    if ( e.target.matchesSelector('myUL li') ) {
//       return "<li>" + item.firstname + item.id + "</li>";
//    }
// }, false);
//   }

  </script>

Answer 1

要在 native JS 中执行此操作，您可以使用 querySelectorAll() 查找元素，然后使用 addEventListener() 添加事件处理程序。另请注意，mouseleave 是在这里使用的更好的事件，因为它可以避免在 mouseout 事件下显示子元素时可能遇到的一些闪烁问题。试试这个:

var liCollection = document.querySelectorAll('#myUL li');
[].forEach.call(liCollection, function(li) {
  li.addEventListener('mouseenter', function() {
    this.querySelector('span').style.display = 'inline';
  });
  li.addEventListener('mouseleave', function() {
    this.querySelector('span').style.display = 'none';
  });  
})

span { display: none; }

<ul id="myUL">
  <li>Foo <span>bar</span></li>
  <li>Lorem <span>impsum</span></li>   
<ul>

话虽如此，CSS 在这里是一个更合适、更好的解决方案:

li span { display: none; }
li:hover span { display: inline; }

<ul id="myUL">
  <li>Foo <span>bar</span></li>
  <li>Lorem <span>impsum</span></li>   
<ul>