JSFiddle - React, Tailwind, and code Playground

by Edward

JavaScript

var url = "https://cors-test.dev/test";
var xhr = new XMLHttpRequest();
xhr.open("GET", url);
xhr.onreadystatechange = function() { console.log('state', xhr); };
xhr.onload = function() {
    console.log('load', xhr, xhr.getResponseHeader('ETag')); 
    var etag = xhr.getResponseHeader('ETag');

    var xhr2 = new XMLHttpRequest();
    xhr2.open("GET", url);
    xhr2.setRequestHeader("If-None-Match", etag);
    xhr2.onreadystatechange = function() { console.log('state', xhr2); }
    xhr2.onload = function() { console.log('load', xhr2); }
    xhr2.send();
};
xhr.send();