Can someone explain to me what these errors mean?

I need the answers for a school project.

Error 1 "Uncaught TypeError: Cannot read property 'getBoundingClientRect' of null"
Error 2 "Uncaught TypeError: Cannot read property 'dom' of null"

Can someone explain to me what these errors mean?

I need the answers for a school project.

Error 1 "Uncaught TypeError: Cannot read property 'getBoundingClientRect' of null"
Error 2 "Uncaught TypeError: Cannot read property 'dom' of null"

• javascript

• 4 You try to read some properties from a variable that is null. Don't you get more information in the messages, like line numbers or file-names? If you are getting them in a browser, all modern browsers have inspectors with good debuggers, try to use them. – Some programmer dude Commented Oct 22, 2015 at 8:26
• 1 Please post a Minimal, Complete, and Verifiable example – kittikun Commented Oct 22, 2015 at 8:36

1 Answer 1

It means you are trying to use a property on something that is null. Make sure you have an object to operate on before trying to use the property. I.e getBoundingClientRect expects a dom element.

One way to select a dom element is by id:

var element = document.getElementById('myElement');

More about selecting dom elements here.