I need to insert the current date & time as a variable into a Form which is being sent to a credit card payment processor using the POST method. The page is in HTML but PHP or Javascript is possible if required.

1) I want to use the current date & time (including seconds):
<input type="hidden" name="trans_id" value="YYYYMMDDHHMMSS">

2) I want to use the current date:
<input type=”hidden” name=”repeat” value=”YYYYMMDD/monthly/12:50”>

I'm guessing this is quite simple but not too sure how to do it

Relatively simple at least,

<script type="text/javascript">
function dateString(which) {
var retVal = "";
var date = new Date();

var Y = date.getFullYear().toString();
var M = (date.getMonth()+1).toString();
	if (M.length == 1) {
		M = "0" + M;
	}
var D = date.getDate().toString();
	if (d.length == 1) {
		d = "0" + d;
	}
var h = date.getHours().toString();
	if (h.length == 1) {
		h = "0" + h;
	}
var m = date.getMinutes().toString();
var s = date.getSeconds().toString();

if (which == "ID") {
	retVal =  Y+M+D+h+m+s ;
}
if (which == "Rep") {
	retVal =  Y+M+D+"/monthly/"+h+ ":" +m ;
}

return retVal;
}
</script>

<form name="formname" >
<input type="text" name="trans_id" value="YYYYMMDDHHMMSS">
<input type="text" name="repeat" value="YYYYMMDDHHMMSS">
</form>

<script type="text/javascript">
document.forms["formname"].trans_id.value = dateString("ID");
document.forms["formname"].repeat.value = dateString("Rep");
</script>

You really don't want to use JavaScript for this. Why? JavaScript is unsecure because it is client-side scripting and it can be turned off or manipulated and not work in older browsers.
So if JavaScript was turned off or the browser was too old to support it you would get no value and a bunch of messed up JavaScript on the page (unless you use HTML <!-- right after the JavaScript declaration).
Plus the time JavaScript returns is the users system clock time. So in other words I could change my system clocks date and time to July 90th 9190 at 40:20 PM. Not good at all. Someone could attack your script and you wouldn't know it was them because the date wouldn't show as the time when you got attacked so it would be a hard thing to prove.
Now you need to control the data. Your server will control it not the users by using PHP.
Here's a script that can do this -

PHP Code:

<?php
$date_time = date('YmdHis');
$date = date('Ymd\/M\/h\:s');
print "<input type=\"hidden\" name=\"trans_id\" value=\"$date_time\">
<input type=\"hidden\" name=\"repeat\" value=\"$date\">";
?>

An example HTML output of this PHP script would be something alone the lines of -

<input type="hidden" name="trans_id" value="20070712083833">
<input type="hidden" name="repeat" value="20070712/Jul/8:39">

You can format it however you like by editing the PHP variables '$date_time' and '$date' and replacing them with the values in this page - http://us.php.net/manual/en/function.date.php. If you need it reformatted and can't figure it out let me know and I'll do it for you.
That should do it. Hope this helps.

You really don't want to use JavaScript for this. Why? JavaScript is unsecure because it is client-side scripting and it can be turned off or manipulated and not work in older browsers.

You are only half right here.
The rule is to always consider datas comming from a client (browser) to be erroneous, and you must validate them to be sure they are valid, after all... Not the contrario.
Never, ever consider datas sent to your site as being the real one. Even if you compose them yourself in a page. Anything can be forged and faked.

Such validation might become a problem. You'd still have to use server side scripting to make sure it's not below this date and note above the other or manually change it every day. Otherwise just like I said someone could enter a completely false date. Plus if you have it so that the client specifices time via their system clock everyones time will be different.
Say two people submit the same form at the same time. One from France one from the US. The France date will be different from the US date because of the time-zone difference. It could even be off be an entire day! So the time and maybe even day would be of no use even with advanced validation using JavaScript.
This is all speaking for this case only. Besides that I agree completely with what you're saying.

All good stuff, thanks guys.

MATT - I'm a bit confused by the backward and forward slashes in the PHP code ... are they all supposed to be there or did the forum add them by mistake after you'd pasted the code in ?

The \(slash) escapes the "(quote) so that it will appear in the html

PHP Code:

print"/"" 


Outputs

"

I use echo intead of print, but basically I think they are the same

Ok, thanks. But there is something else I don't understand.

I don't want to output the results to HTML. As I stated in my initial email this is to be parsed via POST to a payment processor, so my code currently looks like this:

<form action="https://www.secpay.com/java-bin/ValCard" method="post">
<input type="image" src="x-click-but20.gif" border="0" name="submit">
<img alt="" border="0" src="pixel.gif" width="1" height="1">
<input type="hidden" name="trans_id" value="">
<input type="hidden" name="merchant" value="">
<input type=”hidden” name="repeat" value="">
<input type="hidden" name="currency" value="GBP">
</form>

So how do I insert the output from the PHP script into the "trans_id" and "repeat" values ?

<form action="https://www.secpay.com/java-bin/ValCard" method="post">
<input type="image" src="x-click-but20.gif" border="0" name="submit">
<img alt="" border="0" src="pixel.gif" width="1" height="1">
<input type="hidden" name="trans_id" value="<?php echo $transId;?>">
<input type="hidden" name="merchant" value="">
<input type=”hidden” name="repeat" value="<?php echo $repeat;?>">
<input type="hidden" name="currency" value="GBP">
</form>

Replace $repeat and $transId with your variables, simply.

Thanks for all your help guys. Unfortunately it just got a little more complicated in that I need to increase the month by one.

So, today it should read 20070819 and for example on 19th December 2007 it should read 20080119. Any ideas ?

Currently using this :-

<?php
$date_time = date('YmdHis');
$date = date('Ymd');
?>

PHP Code:

//For reference:
//int mktime ( [int $hour [, int $minute [, int $second [, int $month [, int $day [, int $year [, int $is_dst]]]]]]] )
$timestamp=mktime(date('H'), date('i'), date('s'), date('m')+1, date('d'), date('Y'));
$dateTime=date('YmdHis', $timestamp); 


To summarize it, date() work against the current time represented by a timestamp.
But you can transform any given time by forging the correcponding timestamp, and passing that time to date().
It's what mktime() do. Simply decompose the components of the date you want, and do a +1 on the part you need. If this increment make a change in the month or year, mktime() will handle it.

http://www.php.net/manual/en/function.mktime.php

That all makes sense, thanks. I'll try it and let you know if I get stuck.