Uncaught TypeError: Cannot read property 'appendChild' of null

Question

I\'m getting the following error

Uncaught TypeError: Cannot read property \'appendChild\' of null

myRequest.onreadystatechange @ script.js

Answer 1

There isn't an element on your page with the id "mainContent" when your callback is being executed.

In the line:

document.getElementById("mainContent").appendChild(p);

the section document.getElementById("mainContent") is returning null