Solve - Cannot read property 'getAttribute' of Null in JS

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Borislav Hadzhiev

Wed Oct 20 20212 min read

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Solve - Cannot read property 'getAttribute' of Null #

The "Cannot read property 'getAttribute' of null" error occurs for 2 reasons:

  1. Calling the getAttribute() method on a null value (DOM element that doesn't exist).
  2. Placing the JS script tag above the HTML where the DOM elements are declared.

cannot read property getattribute of null

Here is an example of how the error occurs.

index.js
const el = null; // โ›”๏ธ Cannot read properties of null (reading 'getAttribute') el.getAttribute('id');

To solve the "Cannot read property 'getAttribute' of null" error, make sure the id you're using to get the element exists in the DOM. The error often occurs after providing a non-existent id to the getElementById method.

index.js
const el = document.getElementById('does-not-exist'); console.log(el); // ๐Ÿ‘‰๏ธ null // โ›”๏ธ Cannot read properties of null (reading 'getAttribute') const id = el.getAttribute('id');

We passed a non-existent id to the getElementById method and got a null value back.

Calling the getAttribute() method on a null value causes the error.

To solve the "Cannot read property 'getAttribute' of null" error, place the JS script tag at the bottom of the body tag. The script should run after the DOM elements have been created.

index.html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8" /> </head> <body> <!-- โ›”๏ธ BAD - script runs before button exists โ›”๏ธ --> <script src="index.js"></script> <div id="box">Test</div> </body> </html>

The JS script tag is placed above the code that declares the div element, therefore the div element is not accessible from the index.js file.

index.js
const el = document.getElementById('box'); console.log(el); // ๐Ÿ‘‰๏ธ null // โ›”๏ธ Cannot read properties of null (reading 'getAttribute') const id = el.getAttribute('id');

Instead, move the JS script tag to the bottom of the body tag, after the DOM elements it needs access to.

index.html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8" /> </head> <body> <div id="box">Test</div> <!-- โœ… GOOD - div already exists โœ… --> <script src="index.js"></script> </body> </html>

Now we can access the div element inside of the index.js file.

index.js
const el = document.getElementById('box'); console.log(el); // ๐Ÿ‘‰๏ธ div#box // โœ… Works const id = el.getAttribute('id'); console.log(id); // ๐Ÿ‘‰๏ธ box
If the attribute doesn't exist, the getAttribute method returns either null or an empty string.

Conclusion #

The "Cannot read property 'getAttribute' of null" error occurs when trying to call the getAttribute method on a null value.

To solve the error, run the JS script after the DOM elements are available and make sure you only call the method on valid DOM elements.

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