var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function () {
if (xhr.readyState === 4) {
document.getElementById("para").innerHTML =xhr.responseText;

}
};
xhr.open('GET', 'Intro.html', true);
xhr.send();







Uncaught TypeError: Cannot set property 'innerHTML' of nullxhr.onreadystatechange @ index.html:11
Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check http://xhr.spec.whatwg.org/.