JS how to get server-side time?

Use JS to do time correction, get the local time, there is a bug.

The use of JS can also get to the server time, the principle is to use the AJAX request, the header information returned contains the server-side time information, get to it. Following:

1. Rely on jquery

Code:

function getserverdate () {    returnnewfalse}). getResponseHeader ("Date"));

The above function returns a Date object that must be synchronized when using Ajax, or the time date cannot be returned.

No need to fill out the request link;

If the server time and local time are sometimes poor, you need to make corrections.

2. Native

Code:

functiongetserverdate () {varXHR =NULL; if(window. XMLHttpRequest) {XHR=Newwindow.    XMLHttpRequest (); }Else{//IEXHR =NewActiveobject ("Microsoft")} xhr.open ("GET", "/",false)//false immutable Xhr.send (NULL); varDate = Xhr.getresponseheader ("date"); return Newdate (date);}

Also returned is a Date object, Xhr.open () must use synchronization;

No need to fill out the request link; open,send, and getResponseHeader must be written sequentially.

To use asynchronous requests, you can listen to the onreadystatechange state to do different things.

The code is as follows:

functiongetserverdate () {varXHR =NULL; if(window. XMLHttpRequest) {XHR=Newwindow.    XMLHttpRequest (); }Else{//IEXHR =NewActiveobject ("Microsoft")} xhr.open ("GET", "/",true); Xhr.send (NULL); Xhr.onreadystatechange=function(){        vartime,date; if(Xhr.readystate = = 2) { time= Xhr.getresponseheader ("Date"); Date=NewDate (time);        Console.log (date); }    }}

Using Async is not a convenient time to return.

There are four kinds of readystate, which are convenient for different treatments:

• 0: Request not initialized
• 1: Server Connection established
• 2: Request received
• 3: In Request processing
• 4: The request is complete and the response is ready

Failed state, status value:

$: "OK"

404: Page Not Found

JS how to get server-side time?