Date with server timestamp.

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April 5th, 2007, 01:35 AM

Flash Gordon

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Date with server timestamp.

Hi Gang,

Why does this JS script return the client's local time and not the server's time?

Code:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>


<script type="text/javascript">
<!--
	var timestamp;
	<?php echo "timestamp = " . (mktime() * 1000); ?>
	
	
	function time()
	{
		var date     = new Date(timestamp);
		var hours    = date.getHours();
		var minutes  = (date.getMinutes() < 10) ? "0" + date.getMinutes() : date.getMinutes();
		var seconds  = (date.getSeconds() < 10) ? "0" + date.getSeconds() : date.getSeconds();
		var pst      = (hours>11) ? "PM" : "AM";
		var phrase   = "local time = ";
		timestamp    += 1000;
		
		//return phrase + ((hours%12==0) ? 12 : (hours%12)) + ":" + minutes + ":" + seconds + " " + pst; 
		return phrase + hours + ":" + minutes + ":" + seconds + " " + pst; 
	}
	
	function show()
	{
		document.getElementById("clock").firstChild.nodeValue = time();
	}
	
	window.onload = init;
	
	function init()
	{
		show();
		setInterval("show()", 1000);
	}
-->
</script>
</head>

<body>
	<span id="clock">&nbsp;</span><br  />
	<span id="clock2">Server time = <?php echo date("g:i A", mktime()); ?> </span> <br  />
	<span id="timestamp">php timestamp = <?php echo mktime(); ?> </span> <br  />
</body>
</html>

April 5th, 2007, 01:37 AM

draelon

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Because javascript is a client side technology.

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Draelon

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April 5th, 2007, 03:20 PM

Flash Gordon

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so what? I'm passing it a timestamp and therefore doesn't matter.

April 5th, 2007, 05:51 PM

sizablegrin

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I don't believe that a timestamp is a valid form of data for the Date () constructor (I think they all require a string). Consequently, it's probably just constructing with the current date.

Comments on this post

Tukaro agrees: Nope. I don't know how Date() handles bad input, but that sounds reasonable

Flash Gordon disagrees: RTFM before you make statements you don't know about

April 5th, 2007, 09:44 PM

Tukaro

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As sizablegrin said, the timestamp is not in the correct format for creating a new Date.

Quick guide for creating a date. As you can see, Date() will take a string, but it has to be in a specific format. It will not take in a single number.

Are you not getting a Javascript error after the page loads? (and perhaps every second afterwards).

April 5th, 2007, 11:25 PM

Flash Gordon

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NO...it takes an integer.

LINK

new Date(milliseconds)
milliseconds
Integer value representing the number of milliseconds since 1 January 1970 00:00:00 UTC.

It takes an integer, or it will take a string.

April 6th, 2007, 06:45 AM

Tukaro

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I apologize, I was unaware of that. Looking at your code, I assume you've already tested the output of mktime to ensure it was different than what Javascript was giving.

In that case, I can't see why it would be affecting it. When I return from class I'll try running it on my own PHP host to see if I can remedy the problem from there.

April 6th, 2007, 10:51 AM

sizablegrin

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You are correct. It can take an integer.

Referring to both the PHP manual and the document you linked, I think this is what happens. (My system performs as yours, gives me the local time, despite the fact that my server is 3 timezones away).

The integer returned by MKTIME, as used, represents UTC.

The date object contains both UTC and local time (presumably as defined by the locale settings). The methods used are the local-time methods.

That's my take on it.

Comments on this post

Flash Gordon agrees: Admitting I'm correct is the only smart thing you said in this thread.....

April 6th, 2007, 03:53 PM

Flash Gordon

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Hey guys,

Thanks for still looking into this....

I've tried several methods and always the timestamp is ignored by JS

var date = new Date((timestamp-27000)); still outputs local time.

Quote:

The date object contains both UTC and local time (presumably as defined by the locale settings). The methods used are the local-time methods.

. Yea I was thinking that too, but I tried the getUTCHours() method and it gets the real GMT/UTC time and ignores the timestamp too. Passing a timestamp in the constructor seems rather pointless if there are no methods to take advantage of it.....

#10

April 8th, 2007, 12:55 PM

Flash Gordon

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bump*

#11

April 9th, 2007, 02:13 PM

Flash Gordon

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no love?

#12

April 9th, 2007, 02:51 PM

sizablegrin

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You aren't thinking. Suppose you call me and ask what time it is, not knowing what time zone I'm in. I get the UTC time and give it to you. You can either show it as UTC or your local time. Unless I modify it (correctly, to my local time) before I give it to you, you can't know what my time is.

Comments on this post

Flash Gordon disagrees: Your analogies are spectacular. However, you are just missing the point

#13

April 9th, 2007, 09:29 PM

Flash Gordon

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No....I get it just fine. That is what a timestamp does.

I take it no one knows or cares to answer on this forum.

Comments on this post

sizablegrin disagrees: I disagree strongly, but with uncharacteristic restraint.

#14

April 9th, 2007, 10:14 PM

sizablegrin

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Quote:

Originally Posted by PHP manual for mktime

int mktime ( [int $hour [, int $minute [, int $second [, int $month [, int $day [, int $year [, int $is_dst]]]]]]] )

Returns the Unix timestamp corresponding to the arguments given. This timestamp is a long integer containing the number of seconds between the Unix Epoch (January 1 1970 00:00:00 GMT) and the time specified.

In your case, the time specified is nada. There is nothing here about the server considering its own time zone in providing this value. It is copying that value into a JS expression to be reproduced on the browser. Your browser uses this for a Date object. Your Date object can give you GMT (not precisely the same as UTC, incidentally, but synchronized frequently), or your Date object can give you the local time for that GMT time, according to your locale. If you want the server to give its local time, adjust the timestamp accordingly and feed THAT into your JS assignment.

You've gotten a lot of responses. That's hardly indicative of "no one on this forum knowing or caring." Because you're not paying attention, and because you're frustrated, you're making unwarranted remarks.

Comments on this post

Flash Gordon disagrees: your and idiot

Last edited by sizablegrin : April 9th, 2007 at 10:16 PM.

#15

April 10th, 2007, 01:12 AM

Flash Gordon

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Hmm....you really have no clue what you are talking about!

Quote:

In your case, the time specified is nada.

Absolutely not so! Go learn a little php before you make that remark.

Quote:

There is nothing here about the server considering its own time zone in providing this value.

Are you stupid?
What exactly do you think <?php echo date("g:i A", mktime()); ?> displays?

And everything else you said is wrong too. Stop spaming the thread and stop telling people lies. You are missing leading people.

Fool....

this forum is waste of time if this is the response I'm going to get.

Comments on this post

sizablegrin disagrees: You're the fool. You're discussing "date", there, not "mktime".

Date with server timestamp.

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