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如何在JavaScript中实现自动完成功能

javascripthtml
3
如何使用JavaScript实现自动补全功能。 我正试图在添加的输入框中实现自动补全。
HTML代码：
<input type="text" placeholder="Search Country.." id="data" onkeyup="getValue(this.value)" style="width:150px;padding:5px">
<div class="output"></div>

JavaScript 代码：

<script type="text/javascript">
    var result = document.querySelector('.output');
    var ddata = document.querySelector('#data');
    var Arr = ['India', 'USA','China','Netherlands','Nepal','Japan','Australia']
    
    function autoComplete(Arr, val) {
        return Arr.filter(e => e.toLowerCase().includes(val.toLowerCase()));
    }
    function getValue(val){
        if(!val){
            result.innerHTML='';
            return
        }
        var data = autoComplete(Arr,val);    
        for (var i = 0; i < data.length; i++) {
            ddata.value = data[i];
        }
    }
</script>
3个回答
3

这里有一个很好的例子：

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
* {
  box-sizing: border-box;
}

body {
  font: 16px Arial;  
}

/*the container must be positioned relative:*/
.autocomplete {
  position: relative;
  display: inline-block;
}

input {
  border: 1px solid transparent;
  background-color: #f1f1f1;
  padding: 10px;
  font-size: 16px;
}

input[type=text] {
  background-color: #f1f1f1;
  width: 100%;
}

input[type=submit] {
  background-color: DodgerBlue;
  color: #fff;
  cursor: pointer;
}

.autocomplete-items {
  position: absolute;
  border: 1px solid #d4d4d4;
  border-bottom: none;
  border-top: none;
  z-index: 99;
  /*position the autocomplete items to be the same width as the container:*/
  top: 100%;
  left: 0;
  right: 0;
}

.autocomplete-items div {
  padding: 10px;
  cursor: pointer;
  background-color: #fff; 
  border-bottom: 1px solid #d4d4d4; 
}

/*when hovering an item:*/
.autocomplete-items div:hover {
  background-color: #e9e9e9; 
}

/*when navigating through the items using the arrow keys:*/
.autocomplete-active {
  background-color: DodgerBlue !important; 
  color: #ffffff; 
}
</style>
</head>     
<body>

<h2>Autocomplete</h2>

<p>Start typing:</p>

<!--Make sure the form has the autocomplete function switched off:-->
<form autocomplete="off" action="/action_page.php">
  <div class="autocomplete" style="width:300px;">
    <input id="myInput" type="text" name="myCountry" placeholder="Country">
  </div>
  <input type="submit">
</form>

<script>
function autocomplete(inp, arr) {
  /*the autocomplete function takes two arguments,
  the text field element and an array of possible autocompleted values:*/
  var currentFocus;
  /*execute a function when someone writes in the text field:*/
  inp.addEventListener("input", function(e) {
      var a, b, i, val = this.value;
      /*close any already open lists of autocompleted values*/
      closeAllLists();
      if (!val) { return false;}
      currentFocus = -1;
      /*create a DIV element that will contain the items (values):*/
      a = document.createElement("DIV");
      a.setAttribute("id", this.id + "autocomplete-list");
      a.setAttribute("class", "autocomplete-items");
      /*append the DIV element as a child of the autocomplete container:*/
      this.parentNode.appendChild(a);
      /*for each item in the array...*/
      for (i = 0; i < arr.length; i++) {
        /*check if the item starts with the same letters as the text field value:*/
        if (arr[i].substr(0, val.length).toUpperCase() == val.toUpperCase()) {
          /*create a DIV element for each matching element:*/
          b = document.createElement("DIV");
          /*make the matching letters bold:*/
          b.innerHTML = "<strong>" + arr[i].substr(0, val.length) + "</strong>";
          b.innerHTML += arr[i].substr(val.length);
          /*insert a input field that will hold the current array item's value:*/
          b.innerHTML += "<input type='hidden' value='" + arr[i] + "'>";
          /*execute a function when someone clicks on the item value (DIV element):*/
          b.addEventListener("click", function(e) {
              /*insert the value for the autocomplete text field:*/
              inp.value = this.getElementsByTagName("input")[0].value;
              /*close the list of autocompleted values,
              (or any other open lists of autocompleted values:*/
              closeAllLists();
          });
          a.appendChild(b);
        }
      }
  });
  /*execute a function presses a key on the keyboard:*/
  inp.addEventListener("keydown", function(e) {
      var x = document.getElementById(this.id + "autocomplete-list");
      if (x) x = x.getElementsByTagName("div");
      if (e.keyCode == 40) {
        /*If the arrow DOWN key is pressed,
        increase the currentFocus variable:*/
        currentFocus++;
        /*and and make the current item more visible:*/
        addActive(x);
      } else if (e.keyCode == 38) { //up
        /*If the arrow UP key is pressed,
        decrease the currentFocus variable:*/
        currentFocus--;
        /*and and make the current item more visible:*/
        addActive(x);
      } else if (e.keyCode == 13) {
        /*If the ENTER key is pressed, prevent the form from being submitted,*/
        e.preventDefault();
        if (currentFocus > -1) {
          /*and simulate a click on the "active" item:*/
          if (x) x[currentFocus].click();
        }
      }
  });
  function addActive(x) {
    /*a function to classify an item as "active":*/
    if (!x) return false;
    /*start by removing the "active" class on all items:*/
    removeActive(x);
    if (currentFocus >= x.length) currentFocus = 0;
    if (currentFocus < 0) currentFocus = (x.length - 1);
    /*add class "autocomplete-active":*/
    x[currentFocus].classList.add("autocomplete-active");
  }
  function removeActive(x) {
    /*a function to remove the "active" class from all autocomplete items:*/
    for (var i = 0; i < x.length; i++) {
      x[i].classList.remove("autocomplete-active");
    }
  }
  function closeAllLists(elmnt) {
    /*close all autocomplete lists in the document,
    except the one passed as an argument:*/
    var x = document.getElementsByClassName("autocomplete-items");
    for (var i = 0; i < x.length; i++) {
      if (elmnt != x[i] && elmnt != inp) {
        x[i].parentNode.removeChild(x[i]);
      }
    }
  }
  /*execute a function when someone clicks in the document:*/
  document.addEventListener("click", function (e) {
      closeAllLists(e.target);
  });
}

/*An array containing all the country names in the world:*/
var countries = ["Afghanistan","Albania","Algeria","Andorra","Angola","Anguilla","Antigua & Barbuda","Argentina","Armenia","Aruba","Australia","Austria","Azerbaijan","Bahamas","Bahrain","Bangladesh","Barbados","Belarus","Belgium","Belize","Benin","Bermuda","Bhutan","Bolivia","Bosnia & Herzegovina","Botswana","Brazil","British Virgin Islands","Brunei","Bulgaria","Burkina Faso","Burundi","Cambodia","Cameroon","Canada","Cape Verde","Cayman Islands","Central Arfrican Republic","Chad","Chile","China","Colombia","Congo","Cook Islands","Costa Rica","Cote D Ivoire","Croatia","Cuba","Curacao","Cyprus","Czech Republic","Denmark","Djibouti","Dominica","Dominican Republic","Ecuador","Egypt","El Salvador","Equatorial Guinea","Eritrea","Estonia","Ethiopia","Falkland Islands","Faroe Islands","Fiji","Finland","France","French Polynesia","French West Indies","Gabon","Gambia","Georgia","Germany","Ghana","Gibraltar","Greece","Greenland","Grenada","Guam","Guatemala","Guernsey","Guinea","Guinea Bissau","Guyana","Haiti","Honduras","Hong Kong","Hungary","Iceland","India","Indonesia","Iran","Iraq","Ireland","Isle of Man","Israel","Italy","Jamaica","Japan","Jersey","Jordan","Kazakhstan","Kenya","Kiribati","Kosovo","Kuwait","Kyrgyzstan","Laos","Latvia","Lebanon","Lesotho","Liberia","Libya","Liechtenstein","Lithuania","Luxembourg","Macau","Macedonia","Madagascar","Malawi","Malaysia","Maldives","Mali","Malta","Marshall Islands","Mauritania","Mauritius","Mexico","Micronesia","Moldova","Monaco","Mongolia","Montenegro","Montserrat","Morocco","Mozambique","Myanmar","Namibia","Nauro","Nepal","Netherlands","Netherlands Antilles","New Caledonia","New Zealand","Nicaragua","Niger","Nigeria","North Korea","Norway","Oman","Pakistan","Palau","Palestine","Panama","Papua New Guinea","Paraguay","Peru","Philippines","Poland","Portugal","Puerto Rico","Qatar","Reunion","Romania","Russia","Rwanda","Saint Pierre & Miquelon","Samoa","San Marino","Sao Tome and Principe","Saudi Arabia","Senegal","Serbia","Seychelles","Sierra Leone","Singapore","Slovakia","Slovenia","Solomon Islands","Somalia","South Africa","South Korea","South Sudan","Spain","Sri Lanka","St Kitts & Nevis","St Lucia","St Vincent","Sudan","Suriname","Swaziland","Sweden","Switzerland","Syria","Taiwan","Tajikistan","Tanzania","Thailand","Timor L'Este","Togo","Tonga","Trinidad & Tobago","Tunisia","Turkey","Turkmenistan","Turks & Caicos","Tuvalu","Uganda","Ukraine","United Arab Emirates","United Kingdom","United States of America","Uruguay","Uzbekistan","Vanuatu","Vatican City","Venezuela","Vietnam","Virgin Islands (US)","Yemen","Zambia","Zimbabwe"];

/*initiate the autocomplete function on the "myInput" element, and pass along the countries array as possible autocomplete values:*/
autocomplete(document.getElementById("myInput"), countries);
</script>

</body>
</html>

首先，我们添加了HTML。然后定义了一个包含世界上所有国家的array。var countries = ["Afghanistan"..."Zimbabwe"];接着添加了JavaScript。一些函数是必要的，比如事件监听器，所以它们被添加了进来。最后，在“myInput”上启动了自动完成效果。由于这些示例非常清晰，我不想大惊小怪。如果有什么不明显的地方，请随时问我。

确切地说，列表必须被隐藏，输入框上必须显示文本。 - Muhammad Tufail
2
嗨，有一个叫做datalist的东西，它可以为你完成这个任务。 

<label for="browser">Choose your browser from the list:</label>
<input list="browsers" name="browser" id="browser">

<datalist id="browsers">
  <option value="Edge">
  <option value="Firefox">
  <option value="Chrome">
  <option value="Opera">
  <option value="Safari">
</datalist>

1

这将是一个不错的开端，您将拥有一个带有自动完成值的数组，每次输入值更改时，您都会查看提供的值，并检查是否存在与输入值相关联的值，如果存在，则按照您的样式和说明在UI中显示它。

注：搜索以下一个或多个值["意大利", "西班牙", "葡萄牙", "巴西"]

  let inputField = document.getElementById('input');
  let ulField = document.getElementById('suggestions');
  inputField.addEventListener('input', changeAutoComplete);
  ulField.addEventListener('click', selectItem);

  function changeAutoComplete({ target }) {
    let data = target.value;
    ulField.innerHTML = ``;
    if (data.length) {
      let autoCompleteValues = autoComplete(data);
      autoCompleteValues.forEach(value => { addItem(value); });
    }
  }

  function autoComplete(inputValue) {
    let destination = ["Italy", "Spain", "Portugal", "Brazil"];
    return destination.filter(
      (value) => value.toLowerCase().includes(inputValue.toLowerCase())
    );
  }

  function addItem(value) {
    ulField.innerHTML = ulField.innerHTML + `<li>${value}</li>`;
  }

  function selectItem({ target }) {
    if (target.tagName === 'LI') {
      inputField.value = target.textContent;
      ulField.innerHTML = ``;
    }
  }
<div>
  <label for="input">Input</label>
  <input type="text" id="input" />
  <ul id="suggestions"></ul>
</div>

代码片段来源

确切的说，但是列表必须隐藏，并且在输入框上有一个文本显示。 - Muhammad Tufail
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可以查看英文原文，
原文链接