Extract Date and Time Stamp of a file/image

[007Julien]

Eureka ! I found how to obtain a date with Opera ...
To avoid that the browser tries to read the image lastModified in the cache, you have only to call

dt=LastModUsingHeader('upload.jpg?'+Math.random()); 
// or to modify the function 
function LastModUsingHeader(U) {
    var X = !window.XMLHttpRequest ? new ActiveXObject('Microsoft.XMLHTTP') : new XMLHttpRequest;
    X.open('GET', U+'?'+Math.random(), false);
   	try{ X.send();}catch(y){}
  	var dt=X.getResponseHeader('Last-Modified'); 
	return new Date(dt).toLocaletring(); 
}
// to write
<p>Image uploaded: <i id="ImageDate"></i></p>

<script type="text/javascript">
document.getElementById('ImageDate').innerHTML=LastModUsingHeader('upload.jpg'); 
</script>

This could be applied too to the image src...
It would be better to have a DOCTYPE for the page (See W3C) and to display meta tags to control the cache (See this page) to choose a Meta tag...

<META HTTP-EQUIV="CACHE-CONTROL" CONTENT="NO-CACHE">
<META HTTP-EQUIV="PRAGMA" CONTENT="NO-CACHE">

Otherwise the users could have difficulties to update the page...

[gangerolv]

Thanks to all!

This is the code I'm using and it seems to work for Opera, Firefox and IE. The date/time stamp of a file shows up correctly at local time:

<p>Image uploaded: <i id="getImageDate"></i></p>

<script type="text/javascript">
function LastModUsingHeader(sFile) {
	var X = !window.XMLHttpRequest ? new ActiveXObject('Microsoft.XMLHTTP') : new XMLHttpRequest;
    X.open('GET', sFile, false);
   	try{ X.send();}
	catch(y){}
  	var dtImage=new Date();
	dtImage = X.getResponseHeader('Last-Modified'); 
	return new Date(dtImage).toLocaleString();
}

document.getElementById('getImageDate').innerHTML=LastModUsingHeader('upload.jpg'); ;
	
</script>

[007Julien]

It's could be better to call (See for example this page)

document.getElementById('getImageDate').innerHTML=LastModUsingHeader('upload.jpg?avoidCache='+Math.random()));

For me it's do not work with Opera without this addition.