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DOM Found 2 elements with non unique id

DOM Found 2 elements with non unique id

Resolving the "DOM Found 2 Elements with Non Unique ID" Issue in JavaScript

JavaScript is a powerful programming language that enables developers to create dynamic and interactive web pages. As you delve deeper into JavaScript development, you may encounter various challenges along the way.

One common issue that programmers often face is the "DOM Found 2 Elements with Non-Unique ID" error. In this section, we'll explore what this error means, its potential causes, and how to fix it effectively.

What Does DOM Found 2 Elements with Non Unique ID Mean?

When working with JavaScript and manipulating the Document Object Model (DOM), it's essential to understand the concept of element IDs. Each element in an HTML document can have a unique identifier, which is specified using the "id" attribute.

The "DOM Found 2 Elements with Non-Unique ID" error occurs when the DOM encounters two or more elements with the same ID, violating the uniqueness rule.

Potential Causes of the DOM Found 2 Elements with Non Unique ID Issue

Duplicated IDs: The most common cause of this error is inadvertently assigning the same ID to multiple elements in your HTML markup. This could be an oversight or an unintentional duplication while copying and pasting code.

  1. Dynamic element creation
    If your JavaScript code dynamically generates or modifies HTML elements, there's a possibility of unintentionally creating duplicate IDs. This can happen when the same ID is assigned to multiple elements during runtime.

  2. JavaScript frameworks or libraries
    When using JavaScript frameworks or libraries like React, Angular, or jQuery, they often handle DOM manipulations under the hood.
    If not used correctly, these tools can lead to duplicate IDs, causing the error.

How to Fix the  DOM Found 2 Elements with Non Unique ID  Issue

  1. Identify the duplicated IDs
    The first step in resolving this issue is to locate the elements with the duplicate IDs.
    Inspect your HTML code using browser developer tools, such as the built-in element inspector. Look for elements with identical "id" attributes.

  2. Update the duplicate IDs
    Once you've identified the duplicate IDs, update them to ensure they are unique across the entire HTML document.
    Change the "id" attribute of one of the elements to a different value. It's good practice to choose descriptive and meaningful IDs that reflect the purpose of the element.

  3. Use classes instead of IDs
    Consider using CSS classes instead of IDs if the elements don't require a unique identifier for specific JavaScript operations.
    Classes allow you to group similar elements together and apply styles or functionality to them collectively.

  4. Leverage data attributes
    Another approach is to utilize data attributes, such as "data-*," to store custom data related to an element.
    These attributes don't interfere with the ID uniqueness requirement and can be accessed via JavaScript when needed.

  5. Refactor JavaScript code
    If you're generating elements dynamically or manipulating the DOM programmatically, review your JavaScript code for any instances where you inadvertently assign duplicate IDs.
    Ensure that each dynamically created element has a unique ID.

  6. Leverage JavaScript frameworks or libraries correctly
    If you're using a JavaScript framework or library, consult the documentation to understand the recommended practices for working with element IDs. Follow their guidelines to prevent duplicate ID issues.

  7. Validate your HTML markup
    Consider using an HTML validator tool to ensure your code adheres to standards and best practices.
    These tools can help identify potential issues, including duplicate IDs, and assist in resolving them.


The DOM Found 2 Elements with Non Unique ID error can be a common stumbling block for JavaScript developers.

By understanding the causes of this issue and following the suggested solutions, you can effectively resolve it and ensure the smooth functioning of your JavaScript-powered web pages.

Remember to maintain a clear and organized structure in your HTML documents, avoid duplicated IDs, and leverage alternative approaches like classes or data attributes when appropriate.

By doing so, you'll create more robust and maintainable JavaScript code. Happy coding!

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