问题
Does anyone know, what an XMLHttpRequest enables a web page to do, which cannot be done using a normal HttpRequest?
回答1:
XMLHttpRequest in a standard javascript object that allows you to make HTTP Requests from the browser in javascript.
HttpRequest is a server side object that represents a request to the server.
In summary - one works in the browser, the other in the web server. They also have completely different roles. XMLHttpRequest is for fetching web resources within the browser. HttpRequest represents an incoming request.
来源：https://stackoverflow.com/questions/8668449/xmlhttprequest-vs-httprequest