XMLHttpRequest not adding header - “X-Requested-With: XMLHttpRequest”

Question

I have an ajax call where I used jQuery.ajax() to make a request to an mvc action. This all worked fine. However due to some forms having a file control I changed it from us

Answer 1

I was having troubles with detecting if my request was ajax. So, maybe this sample will save someone a minute or two:

var xmlhttp = new XMLHttpRequest();
xmlhttp.open('GET', URL, true);  // `true` for async call, `false` for sync.

// The header must be after `.open()`, but before `.send()`
xmlhttp.setRequestHeader('X-Requested-With', 'XMLHttpRequest');

xmlhttp.onreadystatechange = function() {
    // 4th state is the last:
    if (xmlhttp.readyState == 4 && xmlhttp.status == 200) { ... }
};
xmlhttp.send();

Tested with Flask.