History of Using XMLHttpRequest

Removed excessive us of the word 'case'

My first spelling & grammar edit

Switch alert() for console.log()

Changing XHR response attributes link from W3C to their last updated document (working draft).

Code format issues and syntax errors

Various other equivalent cleanups

Let's forget about this 3rd parameter and teach people to only do asyn by default. Let's just forget sync xhr ever existed.

Editorial review completed.