A brief analysis of how to convert HTML strings into elements

In modern web development, we often need to convert an HTML string into HTML elements, which are often used in front-end development to render dynamic content, deserialize data in forms, etc. Therefore, it is very important to master the skills of converting HTML strings into HTML elements.

This article will introduce two common methods of converting HTML strings into HTML elements: using the innerHTML attribute and creating a virtual DOM.

Using the innerHTML attribute

The innerHTML attribute is a property of the Element object, used to get or set the HTML content of the current element. We can use it to convert an HTML string into HTML elements.

For example:

const htmlString = '<div><p>Hello World</p></div>';
const div = document.createElement('div');
div.innerHTML = htmlString;

In this example, we first define an HTML string htmlString. Next, we create an empty div element and set htmlString to the innerHTML attribute of the div element. This will convert htmlString to an HTML element and add it to the div element.

The advantage of using the innerHTML attribute is that it is easy to use and has better performance. However, it is important to note that it has some security risks. Since it allows scripts to be embedded in HTML, there is a risk of script injection if we use HTML strings from untrusted sources. Therefore, when using the innerHTML attribute, be sure to ensure that the source of the HTML string is trustworthy.

Create virtual DOM

In addition to the innerHTML attribute, we can also use virtual DOM to convert an HTML string into an HTML element. Virtual DOM refers to a JavaScript object that simulates the structure of an HTML document.

The creation process of virtual DOM includes the following steps:

1. Convert HTML string to virtual DOM object
2. Create HTML elements based on virtual DOM object

First of all, we can use some libraries, such as dompurify, sanitize-html, etc. to filter and parse HTML strings to get safe HTML code blocks. Then, we can use virtual DOM libraries, such as React, Vue, etc., to convert HTML code blocks into virtual DOM objects, as follows:

import { h } from 'snabbdom';

const htmlString = '<div><p>Hello World</p></div>';
const vnode = h('div', {}, htmlString);

In this example, we use the Snabbdom virtual DOM library, and use The h function creates a virtual DOM node vnode. In the h function, the first parameter represents the node type, the second parameter represents the attribute, and the third parameter represents the content.

Next, we can use virtual DOM libraries, such as ReactDOM, Vue, etc., to convert virtual DOM objects into HTML elements, as follows:

import { h } from 'snabbdom';
import { toVNode } from 'snabbdom-jsx';
import snabbdom from 'snabbdom';
import snabbdomModules from 'snabbdom/modules';
import { render } from 'react-dom';

const htmlString = '<div><p>Hello World</p></div>';
const vnode = h('div', {}, htmlString);
const domContainer = document.createElement('div');
render(toVNode(vnode), domContainer);

In this example, we use the virtual React DOM library, and use the toVNode function to convert vnode into React's virtual DOM object. Use the render function to render virtual DOM objects into the page.

The advantage of using virtual DOM is that it is highly secure and not susceptible to script injection attacks. At the same time, virtual DOM can also provide better performance and a better development experience, because they allow us to abstract the application state into data, making the code easier to understand and debug.

Conclusion

This article introduces two common methods of converting HTML strings into HTML elements: using the innerHTML attribute and creating a virtual DOM. Using the innerHTML attribute is simple and easy to use, but there are security risks; the advantage of virtual DOM is that it is highly secure and provides better performance and development experience. In actual development, we should choose a method that suits us based on the actual situation.

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