Is it possible to retrieve the last modified date of a file using Javascript?

Question

I have a set of links on a web page that link to PDF forms and .doc forms. These files are not stored in a database, simply stored as they are, locally on the server. Is i

Answer 1

This seems to be useful, and works for me - giving you the 'local' date

document.lastModified 

Compared to the above selection of req.getResponseHeader() it's one less round trip/http call.

Answer 2

File.lastModified

You can use the File.lastModified property to obtain the last modified date of a file as the number of milliseconds since the Unix epoch.

Example:

const file = document.getElementById('input').files[0];
const lastModifiedDate = new Date(file.lastModified);

console.log(`Last Modified Date: ${lastModifiedDate}`);

Answer 3

No, it's not. You can't access the file system through JavaScript

Answer 4

If an interface is exposed through HTTP, you can. Another way of saying: expose a WebService end-point to gain access to this information.

Of course, you can't have direct access to the filesystem for security reasons.

Answer 5

If it's on the same server as your calling function you can use XMLHttpRequest-

This example is not asynchronous, but you can make it so if you wish.

function fetchHeader(url, wch) {
    try {
        var req=new XMLHttpRequest();
        req.open("HEAD", url, false);
        req.send(null);
        if(req.status== 200){
            return req.getResponseHeader(wch);
        }
        else return false;
    } catch(er) {
        return er.message;
    }
}

alert(fetchHeader(location.href,'Last-Modified'));