How do I check if file exists in jQuery or pure JavaScript?

Question

How do I check if a file on my server exists in jQuery or pure JavaScript?

Answer 1

Here's my working Async Pure Javascript from 2020

function testFileExists(src, successFunc, failFunc) {
    var xhr = new XMLHttpRequest();
    xhr.onreadystatechange = function () {
        if (this.readyState === this.DONE) {
            if (xhr.status === 200) {
                successFunc(xhr);
            } else {
                failFunc(xhr);
            }
        }
    }
    // xhr.error = function() {
    //     failFunc(xhr);
    // }
    // xhr.onabort = function() {
    //     failFunc(xhr);
    // }
    // xhr.timeout = function() {
    //     failFunc(xhr);
    // }
    xhr.timeout = 5000;           // TIMEOUT SET TO PREFERENCE (5 SEC)
    xhr.open('HEAD', src, true);
    xhr.send(null);               // VERY IMPORTANT
}
function fileExists(xhr) {
    alert("File exists !!  Yay !!");
}
function fileNotFound(xhr) {
    alert("Cannot find the file, bummer");
}
testFileExists("test.html", fileExists, fileNotFound);

I could not force it to come back with any of the abort, error, or timeout callbacks. Each one of these returned a main status code of 0, in the test above, so I removed them. You can experiment. I set the timeout to 5 seconds as the default seems to be very excessive. With the Async call, it doesn't seem to do anything without the send() command.