How to use Vue to implement lazy loading effects for images

How to use Vue to implement lazy loading effects for images

In modern web design, images occupy a large proportion. However, loading all images at once may cause the web page to load slowly and affect the user experience. In order to solve this problem, we can use the lazy loading effect of images, that is, the image will only be loaded when the user scrolls to the visible area. This article will introduce in detail how to use Vue.js to implement lazy loading effects for images, and provide specific code examples.

Step 1: Install Vue.js

First, install Vue.js in your project. You can install Vue.js by referencing the Vue.js CDN address directly in the HTML file, or by installing Vue.js through npm. If you choose to use a CDN, you can insert the following code snippet into the tag of your HTML file:

<script src="https://cdn.jsdelivr.net/npm/vue@2.6.2/dist/vue.min.js"></script>

If you choose to use npm to install Vue.js, you can Run the following command to install:

npm install vue

Step 2: Create a Vue instance

In the HTML file, create a <div> element as a mount for the Vue instance Point:

<div id="app"></div>

Then, in the JavaScript file, create a Vue instance and mount it on the <div> element created previously:

var app = new Vue({
  el: '#app',
});

Step 3 : Create a picture component

Next, we create a picture component, which will be responsible for displaying pictures and implementing lazy loading effects. We can define this component in the components option of the Vue instance. The specific code is as follows:

Vue.component('lazy-image', {
  props: ['src'],
  data: function() {
    return {
      loaded: false,
    };
  },
  methods: {
    loadImage: function() {
      var image = new Image();
      image.src = this.src;
      image.onload = () => {
        this.loaded = true;
      };
    },
  },
  mounted: function() {
    this.loadImage();
  },
  template: `
    <div>
      <img  src="/static/imghw/default1.png"  data-src="src"  class="lazy"  v-if="loaded" : alt="How to use Vue to implement lazy loading effects for images" >
      <div v-else class="placeholder"></div>
    </div>
  `,
});

In the above code, we created a component named lazy-image. This component accepts a src attribute, which represents the URL of the image to be displayed. In the data option of the component, we define a loaded attribute to indicate whether the image has been loaded.

In the methods option of the component, we created a loadImage method. This method is called when the component is mounted on the page. In the loadImage method, we create a new image object, assign the src attribute to it, and set the loaded attribute to when the image is loaded. true.

Finally, in the component's template option, we define the component's rendering template. When the loaded attribute is true, the image is displayed, otherwise a placeholder is displayed.

Step 4: Use the image component

We can use the image component in the template of the Vue instance, and use the <lazy-image> tag where the image needs to be displayed. , and pass the URL of the image to be displayed to the component as the src attribute. The specific code is as follows:

<lazy-image src="path/to/image.jpg"></lazy-image>

With the above code, the image will only start loading when the user scrolls to the visible area.

To sum up, we have implemented the lazy loading effect of images through Vue.js. When the user scrolls to the image position, the image will start loading, which can greatly improve the loading speed and user experience of the web page. The above code example provides a basic implementation method, and you can further expand and optimize it according to actual needs.

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