(window.ActiveXObject) What does it mean?
Solution: Determine whether the browser supports ActiveX controls. If the browser supports ActiveX controls, you can use
var xml=new ActiveXObject("Microsoft.XMLHTTP"); to create an XMLHttpRequest object (this (in versions before IE7); in newer IE versions, you can use var xml=new ActiveXObject("Msxml2.XMLHTTP") to create an XMLHttpRequest object; and in IE7 and non-IE browsers, you can use var xml= new XMLHttpRequest() creates an XMLHttpRequest object.
When creating an XMLHttpRequest object, browser compatibility issues must be taken into consideration
Creating an XMLHTTPRequest object
By the way, speaking of differences, let’s take a look here How to declare (use) it, before using the XMLHTTPRequest object to send requests and process responses, we must use javascript to create an XMLHTTPRequest object. (IE implements XMLHTTPRequest as an ActiveX object, and other browsers [such as Firefox/Safari/Opear] implement it as a native javascript object). Let’s take a look at how to use javascript to create it:
Code: