JavaScript innerHTML vs. textContent: Which Should You Use?

Introduction

When you need to get or set the content of an HTML element using JavaScript, you’ll quickly come across two common properties: innerHTML and textContent. While they might seem similar, they have crucial differences in how they handle content, which impacts security, performance, and behavior. Choosing the right one is essential for writing robust and secure code.

This guide will compare innerHTML and textContent to help you decide which one to use in different scenarios.

What is innerHTML?

The innerHTML property gets or sets the HTML markup contained within an element. When you set innerHTML, the browser parses the string you provide as HTML and rebuilds the DOM tree for that element.

Example:

<div id="my-div">This is some <strong>old</strong> text.</div>

const myDiv = document.getElementById('my-div');

// Getting content
console.log(myDiv.innerHTML);
// Output: This is some <strong>old</strong> text.

// Setting content
myDiv.innerHTML = 'This is some <span>new</span> text.';
// The div now contains the new HTML content, including the span element.

Key Characteristics of innerHTML

• Parses HTML: It recognizes and renders HTML tags.
• Security Risk: It is vulnerable to Cross-Site Scripting (XSS) attacks. If you set innerHTML with untrusted user input, a malicious user could inject a <script> tag or other harmful markup that will be executed by the browser.
• Performance: It is generally slower than textContent because it involves the overhead of parsing HTML and rebuilding the DOM.

What is textContent?

The textContent property gets or sets the raw text content of an element and all its descendants, without any HTML markup.

Example:

<div id="my-div">This is some <strong>old</strong> text.</div>

const myDiv = document.getElementById('my-div');

// Getting content
console.log(myDiv.textContent);
// Output: This is some old text.

// Setting content
myDiv.textContent = 'This is some <span>new</span> text.';
// The div now contains the literal string "This is some <span>new</span> text."
// The <span> tags are not parsed; they are displayed as plain text.

Key Characteristics of textContent

• Plain Text Only: It treats all content as raw text and does not parse HTML tags.
• Secure: It automatically sanitizes the content by rendering HTML tags as literal text, effectively preventing XSS attacks.
• Performance: It is much faster than innerHTML because it involves a direct manipulation of text nodes without any HTML parsing.
• Aware of CSS: textContent returns the text of all elements, including those hidden by CSS (e.g., display: none;). In contrast, the similar innerText property would not include hidden text.

innerHTML vs. textContent: The Showdown

Feature	innerHTML	textContent
Content Type	HTML string	Plain text string
Security	Vulnerable to XSS. Use only with trusted content.	Secure by default. Automatically sanitizes HTML.
Performance	Slower (due to HTML parsing)	Faster (direct text manipulation)
Usage	When you explicitly need to render HTML markup.	When you only need to work with plain text.
Output	Returns HTML tags, comments, and text.	Returns only the text content.

Which One Should You Use?

Here’s a simple rule of thumb:

Always default to textContent unless you have a specific and safe reason to use innerHTML.

• Use textContent when:
  • You are setting text that comes from user input.
  • You only need to display or update plain text.
  • Security and performance are priorities.
• Use innerHTML only when:
  • You are setting content that you have full control over (e.g., a hardcoded template).
  • You explicitly need to generate and insert HTML elements (like <strong>, <span>, <a>, etc.) into the DOM.

A Note on innerText

There is a third, similar property called innerText. It is different from textContent in a few ways:

• innerText is CSS-aware and will not return the text of elements hidden with display: none;.
• innerText triggers a reflow (a performance-heavy recalculation of the layout), whereas textContent does not.
• It has some inconsistent behavior across older browsers.

For these reasons, textContent is generally the preferred property for performance and predictability, unless you specifically need the CSS-aware behavior of innerText.

Conclusion

Understanding the difference between innerHTML and textContent is crucial for writing secure and efficient JavaScript. While innerHTML is powerful for creating dynamic HTML, its security risks cannot be ignored. textContent provides a safer and faster alternative for all plain-text operations.

By making a conscious choice between the two, you can protect your applications from XSS vulnerabilities and ensure better performance. Remember: use textContent by default, and innerHTML with caution.