To replace words in the body text with JavaScript, we call the replace method.
For instance, we write
document.body.innerHTML = document.body.innerHTML.replace("hello", "hi");
to call document.body.innerHTML.replace with 'hello' and 'hi' to replace 'hello' with 'hi' in the body element.
And then we assign the replaced string back to document.body.innerHTML to update the body element’s contents with the new string.
