Ajax processing 301 302

Some Ajax frameworks encapsulate the processing of 301,302 and other return codes, such

 
Function updatepage () {If (request. readystate = 4) {If (request. status = 200) {var response = request. responsetext. split ("|"); document. getelementbyid ("order "). value = response [0]; document. getelementbyid ("Address "). innerhtml = response [1]. replace (/\ n/g, "<br/>");} else alert ("status is" + request. status );}}
 

If the server returns 301, or the 302 front-end AjaxProgramWhat will be done?

• 301: Permanent movement
• 302: Found (the request is redirected to another URL/uri)
• 305: Use proxy (the request must use a proxy to access the requested resource)

Ajax programmers may not be too concerned about redirection issues due to two reasons:

• First, Ajax applications are usually written for a specific server-side script, Servlet, or application. For those components that you can't see and disappear, the Ajax programmer is not very clear. So sometimes you know that the resource has been moved (because you have moved it, or you have moved it by some means). Next, you need to modify the URL in the request without encountering such a result.
• More importantly, Ajax applications and requests are encapsulated in the sandbox. This means that the domain of the web page that provides Ajax requests must be the domain that responds to these requests. Therefore, the web pages provided by ebay.com cannot generate an Ajax-style request for a script running on Amazon.com; ajax applications on ibm.com cannot send requests to Servlets running on netbeans.org.

My question is, why do we need to use 301 and 302 response on our own server?