CODEWITHSUNDEEP
javajspdatetime
Dharm
Dharm

Reputation: 87

Displaying server time on jsp page

I am displaying server time on a jsp page, and in order to display correct time, I have to call that jsp page to refresh the displayed time which leads to many requests to the server.

Can anyone suggest any improvement on the way I'm displaying server time on jsp page without sending request frequently? 

function displayserver(){
    $.post("DisplayServerTime.jsp","",function(data,status, req){
         $("#DisplayTimeSection").text(req.responseText.trim());
    });
}

$(function(){
setInterval(
function(){
    displayserver();
}
, 30000);
});

Upvotes: 0

Views: 5878

Answers (6)

Abhishek Singh
Abhishek Singh

Reputation: 9729

Step 1 : Get the server Date object on your page using request.getAttribute("serverDate"); or session.getAttribute("serverDate");

Step 2 : Create a javascript Object from the date recieved in step 1

Step 3 : Add a client-side setInterval it will increment Step2 object by 1 second and set the time back in the page.

Upvotes: 0

Baji Shaik
Baji Shaik

Reputation: 1122

Add a label where ever you want to show the server Time

<strong>Server Time&nbsp;:&nbsp;&nbsp;</strong><label id="timelable"></label>

And then add the following java script code at the end of the jsp inside the body tag

<script type="text/javascript">
        var myVar = setInterval(function(){ myTimer() }, 1000);
        var jsVar=  <%=java.util.Calendar.getInstance().getTimeInMillis()%>;
        var timeZoneOffset=<%=java.util.TimeZone.getDefault().getOffset(System.currentTimeMillis())%>;

        jsVar=jsVar+timeZoneOffset;
        function myTimer() {
        jsVar=jsVar+1000;
        var d = new Date(jsVar);
        var t=d.toUTCString();
    document.getElementById("timelable").innerHTML = t;
}

        </script>

Thats it now you will see the server time running in you jsp.

Upvotes: 0

Barun
Barun

Reputation: 1622

The idea here is to call the time.jsp once every five times when the displayserver method is called. For the other 4 times when the time.jsp is not called, we update a javascript Date object and display it.

<script type="text/javascript">
var jsVar=0;
var d = new Date();
var timeInterval = 3000;

var doPost=true;
var postCount=0;


function displayserver(){
    if(doPost && postCount == 0){
        $.post("time.jsp","")
         .done(function(msg){
            jsVar = msg;
            doPost = false;
        });
    }else{
        postCount++;
        jsVar = d.getTime() + timeInterval;
        if(postCount == 4){
            postCount=0;
            doPost = true;
        }
    }
    d.setTime(jsVar);
    $("#DisplayTimeSection").text(d);
}

$(function(){
setInterval(
function(){
    displayserver();
}
, timeInterval);
});

</script>

Upvotes: 0

Suresh Atta
Suresh Atta

Reputation: 121998

without sending request frequently.

While loading the page get the server time in long and create a Date(millis) Object with Javascript.

Then use setInterval() with 1 sec and display.

In you Jsp

var jsVar=  <% dateMillis %>;   // server millis

and javascript date formation 

var d = new Date();
d.setTime(jsVar);   // server millis ex :1332403882588

Then show in JS

var x = document.getElementById("timelable");
x.innerHTML=d.getMilliseconds(); // Modify as per your format

Then 

window.setInterval(Yourfunction,milliseconds);

Then in your Yourfunction add 1 sec to your millis and refresh lable

Upvotes: 0

Tudor Vintilescu
Tudor Vintilescu

Reputation: 1460

Get the server time when you first load the page, then find out the time difference between the client's time and the server's time.

Second, run recurrently a function (using setInterval()). On each invocation get the client time and add the time difference you got at the first step, then display it.

You'll need to run the interval function something like twice per second to be sure you don't skip seconds.

Upvotes: 1

Silviu Burcea
Silviu Burcea

Reputation: 5348

This can be done easily. Just send to the client the server time and add a client-side setInterval that will get the time, increment by 1 second and set the time back in the page.

Note that if you want the client time, you can get the time as easy as new Date() in JS and apply the setInterval too.

Upvotes: 0

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