Uncaught TypeError: Cannot set property 'playbackRate' of null at <anonymous>:1:46

This error occurs when you are trying to set the property 'playbackRate' on a null value.

To fix this error, you need to make sure that the object you are trying to access is not null or undefined. You can do this by checking if the object exists before trying to set its properties.

For example, if you are trying to set the playbackRate property of an HTML5 video element, you can first check if the element exists using the following code:

let video = document.getElementById('my-video');
if (video) {
  video.playbackRate = 2.0;
}

This code checks if the element with ID 'my-video' exists in the document. If it does, it sets the playbackRate property to 2.0. If it doesn't, the code will not execute the second line, avoiding the null error.