TypeError: Cannot read properties of null (reading 'addEventListener')

This error occurs when you try to access a property or method of a null value in JavaScript. The specific error message "Cannot read properties of null (reading 'addEventListener')" indicates that you are trying to add an event listener to an element that does not exist in the DOM.

To fix this error, you need to make sure that the element you are trying to add the event listener to actually exists in the DOM. You can check if an element exists by using the `document.getElementById()` method or other methods like `document.querySelector()`.

Here's an example of how you could check if an element exists before adding an event listener:

const element = document.getElementById('my-element');

if (element) {
    element.addEventListener('click', () => {
        // Do something when the element is clicked
    });
} else {
    console.error('Element not found in DOM');
}

In this example, we first check if the element with the ID "my-element" exists using `document.getElementById()`. If it does exist, we add an event listener to it. If it doesn't exist, we log an error message to the console.