Create li from loop through array and display to H

问题:

I am learning javaScript and I want to loop array and display to HTML as a list. How can I do that?

Array: var array = ['Slide 1', 'Slide 2', 'Slide 3', 'Slide 4', 'Slide 5', 'Slide 6', 'Slide 7', 'Slide 8', 'Slide 9'];

javascript:

function listItem(item){
  for (var i = 0; i < item.array.length; i++){
    var list = item.array[i];
    
    list = document.createElement('li');
    document.getElementByClass('box').appendChild(list);
    
    console.log(list);
  }  
 }

<div class ="box"><ul></ul></div>

回答1:

Whilst all the supplied answers work and are fine - they all suffer from the same issue - in that they append the element to the DOM with each iteration. With a small list this will not be an issue, but if you are dealing with a large number of elements that you want in your list - the constant manipulation of hte DOM will have a performance cost.

It is far better (IMO) to build a single string of the li's and then when the array is fully iterated through - pass the string to the UL using .innerHTML - in the DOM in a single action. Same result - but faster.

var slides = ["slide 1", "slide 2", "slide 3", "slide 4", "slide 5"]
var str = '<ul>'

slides.forEach(function(slide) {
  str += '<li>'+ slide + '</li>';
}); 

str += '</ul>';
document.getElementById("slideContainer").innerHTML = str;

<div id="slideContainer"></div>

回答2:

Fairly simple:

var array = ["slide 1", "slide 2", "slide 3", "slide 4", "slide 5"]

array.forEach(function(item) {
  var li = document.createElement("li");
  var text = document.createTextNode(item);
  li.appendChild(text);
  document.getElementById("myUl").appendChild(li);
});

<ul id="myUl"></ul>

This code does the following:

• For each item of the array:
  1. Create a new <li>
  2. Create a text node with the text from the array
  3. Append the text to the <li>
  4. Append the <li> to the <ul>

This all becomes much simpler if you use jQuery:

var array = ["slide 1", "slide 2", "slide 3", "slide 4", "slide 5"];
array.forEach(function(item) {
  $("#myUL").append("<li>" + item + "</li>");
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<ul id="myUL">
</ul>

EDIT: If you want to use a normal for loop instead of forEach, you can do like so:

var array = ["slide 1", "slide 2", "slide 3", "slide 4", "slide 5"];
for (i = 0; i < array.length; i++) {
  var li = document.createElement("li");
  var text = document.createTextNode(array[i]);
  li.appendChild(text);
  document.getElementById("myUl").appendChild(li);
}

<ul id="myUl"></ul>

The only difference in this code is that instead of using the built-in forEach method to loop through the array and perform operations on each element, we instead manually loop through the indices of the array.

回答3:

You could use the ES6 method reduce and template literals. You could use them like this:

var array = ['Slide 1', 'Slide 2', 'Slide 3', 'Slide 4', 'Slide 5', 'Slide 6', 'Slide 7', 'Slide 8', 'Slide 9'],
  // Reduce will iterate over all the array items and returns a single value.
  listItems = array.reduce((result, item) => {
    // Add a string to the result for the current item. This syntax is using template literals.
    result += `<li>${item}</li>`;
    
    // Always return the result in the reduce callback, it will be the value or result in the next iteration.
    return result;
  }, ''); // The '' is an empty string, it is the initial value result.
  // Get the element from the DOM in which to display the list, this should be an ul or ol element.
  resultElement = document.getElementById('result');

// Set the inner HTML
resultElement.innerHTML = listItems;

<ul id="result"></ul>

For more information on reduce see here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce. And if you want to know more about template literals check here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals

回答4:

Convert the array into a string by using Array#join and using list item tags as separators. Add the start and end tag manually using string concatenation (+). Assign the string to the list element (ul#target) using Element#innerHTML:

var array = ['Slide 1', 'Slide 2', 'Slide 3', 'Slide 4', 'Slide 5', 'Slide 6', 'Slide 7', 'Slide 8', 'Slide 9'];

target.innerHTML = '<li>' + array.join('</li><li>') + '</li>';

<ul id="target"></ul>

回答5:

Try this ,also you can add to the list

var arr = [
  Math.random().toFixed(2),
  Math.random().toFixed(2),
  Math.random().toFixed(2),
  Math.random().toFixed(2),
  Math.random().toFixed(2)
];

console.log(arr);
var ul = document.createElement('ul');
ul.className = 'myUL';
document.getElementById('container').appendChild(ul);

function myFunction() {
     
    // for(var i =0;i<5;i++){
    //   arr.push(Math.random().toFixed(2));
    // }
  create(arr);
}

function create(arr){
  arr.forEach(function(data){
  var li = document.createElement('li');
  ul.appendChild(li);
  li.innerHTML  += data;
  li.className = "myList";
});
}create(arr);

#container .myUL{
  padding:0px;
}

#container .myUL .myList {
  list-style-type: none;
  border:1px solid grey;
  padding:5%;
  border-radius:5px;
  margin:4px;
}
.click{
  width:80px;
  height:30px;
  border-radius:5px;
  color:#fff;
  background:#323232;
  font-size:15px;
    
}

 
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JS Bin</title>
</head>
<body>
  <!-- create a ul li using js  -->

  <button class="click" onclick="myFunction()">Click Me</button>
<div id="container"></div>
</body>
</html>