状态码304

Question

I am new to Javascript and server-side programming. I am trying to send a GET request to load an image from my blog: http://jsafaiyeh.github.io/img/suw_background.png

function imgLoad(url) {
return new Promise(function(resolve, reject) {

  var request = new XMLHttpRequest({mozSystem: true});
  request.open('GET', url);
  request.responseType='blob';

  request.onload = function() {
    if (request.status >= 200 && request.status < 400) {
      resolve(request.response);
    } else {
      reject(Error('Image did\'t load successfully; error code '+ request.statusText));
    }
  };

  request.onerror= function() {
    reject(Error('There was a network Error'));
  };
  request.send();
});
}

var body = document.querySelector('body');
var myImage = new Image();

imgLoad('http://jsafaiyeh.github.io/img/suw_background.png').then(function response() {
  var imageURL = window.URL.createObjectURL(response);
  myImage.src = imageURL;
  body.appendChild(myImage);
}, function(Error) {
  console.log(Error);
});

I get status code 304. However, the image still does not load onto the page. Any help would be appreciated.

Answer 1

You have wrong function signature. It should be like this:

imgLoad('http://jsafaiyeh.github.io/img/suw_background.png').then(function (response) {
  var imageURL = window.URL.createObjectURL(response);
  myImage.src = imageURL;
  body.appendChild(myImage);
}, function(Error) {
  console.log(Error);
});

Working demo on JSFiddle (at least in Chrome).

Instead of passing named function, called response you probably wanted response to be in argument list. So, instead of function response() , you need function (response) . You didn't get error that response was undefined, because it actually was declared, but it wasn't expected result from promise, but function.