Uncaught TypeError: Cannot read properties of undefined (reading 'style')

This error occurs when you try to access the 'style' property of an undefined variable or object. It means that the code is trying to access the 'style' property of something that doesn't exist.

To fix this error, you need to make sure that the variable or object you are trying to access exists and has a 'style' property. You can use console.log statements to check the value of the variable or object and see if it is undefined or null. If it is undefined, you need to initialize the variable or object before accessing its 'style' property.

Here's an example of how to fix this error:

// Incorrect code that causes the error
var element;
element.style.color = 'red';

// Correct code that fixes the error
var element = document.getElementById('my-element');
if (element) {
  element.style.color = 'red';
}

In the corrected code, we check if the 'element' variable is not null or undefined before accessing its 'style' property. If it is null or undefined, we don't try to access the 'style' property and avoid the error.