Ajax obtains the current server time

Use ajax to obtain the date value on the response header. Note the time zone. In the chrome development tool header, all values are Greenwich Mean Time, which is 8 hours less than Beijing time, the obtained time zone is related to the server settings. The following method is recommended:

// Obtain the current server time from the response header. The function getServerTime () {var xmlHttp = false; try {xmlHttp = new ActiveXObject ("Msxml2.XMLHTTP ");} catch (e) {try {xmlHttp = new ActiveXObject ("Microsoft. XMLHTTP ") ;}catch (e2) {xmlHttp = false ;}} if (! XmlHttp & typeof XMLHttpRequest! = 'Undefined') {xmlHttp = new XMLHttpRequest ();} xmlHttp. open ("GET", window. location. href. toString (), false); xmlHttp. setRequestHeader ("Range", "bytes =-1"); xmlHttp. send (null); var severtime = new Date (xmlHttp. getResponseHeader ("Date"); return severtime}

In addition, there is a problem that the cache does not update the time through the ajax method of jquery.
Htmlobj = $. ajax ({url: "a.txt", async: false });
$ ("# MyDiv" ).html (htmlobj. responseText );
ResponseText: returned content
Async: false indicates that the Code after the return value is executed (synchronous thread)
Htmlobj. getResponseHeader ("Date ")
Obtain the time in the response header (Greenwich Mean Time, 8 hours slower than Beijing Time ),
When cache exists, the value in IE is null, and chrome time is not updated.
Firefox has frequent requests and there is a delay in time. The time will not be updated in a certain period of time (about one minute from the previous refresh ).