I am trying to append the contents of a .html file to the body of my main page. Basically, I am trying to make a reusable chunk of html that I can load into any page with a
you need a reference to DOM to know where to innest your loaded page. in your case you could think about appending it to body like this:
function importHTML(url_) {
var request = new XMLHttpRequest();
request.addEventListener("load", function(event_) {
document.body.innerHTML += this.responseText
}, false);
xmlhttprequest.open("POST", url_, true);
xmlhttprequest.send(null);
}