Uncaught TypeError: Cannot set property ‘hidden’ of null

Normally, the error message “Uncaught TypeError: Cannot set property ‘hidden’ of null” is a JavaScript error that occurs when you are trying to access or modify the ‘hidden’ property of an element, but the element itself is null or does not exist in the DOM (Document Object Model).

Here’s an analysis of the error and a solution:

Analysis:

• The error message indicates that you are attempting to set the ‘hidden’ property of an element to null. In JavaScript, the ‘hidden’ property is typically used to hide or show elements by assigning a boolean value (true or false) to it.
• The error occurs because you are trying to access a property of an element that is not present in the DOM, which results in a null reference.

Solution:
To resolve this error, you need to ensure that the element you are trying to access or modify exists in the DOM before attempting to work with it. Here are some steps to fix it:

1. Check Element Existence:
   Before accessing or modifying an element, verify that the element exists in the DOM. You can use methods like document.querySelector() to select elements by their CSS selectors and check if the result is not null.

   const element = document.querySelector('#your-element-id');
   if (element !== null) {
       // Element exists, you can safely work with it
       element.hidden = true; // or element.hidden = false;
   } else {
       console.error("Element not found in the DOM");
   }

2. Use Event Listeners:
   If you are trying to manipulate elements in response to user actions or events (e.g., button clicks), make sure to add event listeners that trigger your code only when the relevant element is interacted with. Inside the event listener, you can safely access the element.

   const button = document.querySelector('#your-button-id');
   button.addEventListener('click', () => {
       const element = document.querySelector('#your-element-id');
       if (element !== null) {
           element.hidden = true; // or element.hidden = false;
       } else {
           console.error("Element not found in the DOM");
       }
   });

3. Check HTML Structure:
   Ensure that your HTML structure matches your JavaScript code expectations. If an element with a specific ID or class is expected to exist, make sure it is correctly defined in your HTML markup.
4. Graceful Error Handling:
   Consider adding graceful error handling to your code to handle cases where the element is not found more gracefully, such as displaying a user-friendly message or handling the situation based on your application’s requirements.

By following these steps and verifying the existence of the element in the DOM before attempting to manipulate it, you can prevent the “Uncaught TypeError: Cannot set property ‘hidden’ of null” error in your JavaScript code.