JavaScript AJAX Basics (retiring) AJAX and APIs Adding jQuery

Ilya Chekharin
Ilya Chekharin
6,341 Points

"This"

$('button').removeClass("selected"); -- Why does this work? $(this).removeClass("selected");--And this doesn't?

$(document).ready(function(){
  $('button').click(function(){
    $('button').removeClass("selected");
    $(this).addClass("selected");
    var flickerAPI = "http://api.flickr.com/services/feeds/photos_public.gne?jsoncallback=?";
    var animal = $(this).text();
    var flickrOptions = {
      tags: animal,
      format: "json"
    };
    function displayPhotos(data){
      var photoHTML = '</ul>';
  $.each(data.items, function(i, photo){
    photoHTML += '<li class="grid-25 tablet-grid-50">';
    photoHTML += '<a href="" '  + photo.link + 'class="image">';
    photoHTML += '<img src="' + photo.media.m + '"></a></li>';
    photoHTML += '</ul>';
  });
    photoHTML += '</ul>';
      $('#photos').html(photoHTML);
  }
    $.getJSON(flickerAPI, flickrOptions, displayPhotos);
  });
}); // end ready
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>AJAX Flickr Photo Feeder</title>
  <link href='http://fonts.googleapis.com/css?family=Varela+Round' rel='stylesheet' type='text/css'>
  <link rel="stylesheet" href="css/main.css">
  <script src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
  <script src="js/flickr.js"></script>
</head>
<body>
  <div class="grid-container centered">
    <div class="grid-100">
      <div class="contained">
        <div class="grid-100">
          <div class="heading">
            <h1>Flickr Photo Feeder</h1>
            <p>Choose which kind of animal you'd like to return photos of...</p>
          </div>
          <ul class="filter-select">
            <li><button>Dog</button></li>
            <li><button>Cat</button></li>
            <li><button>Moose</button></li>
          </ul>
        </div>

        <div id="photos">

        </div>
      </div>
    </div>
  </div>
</body>
</html>
Seth Kroger
Seth Kroger
Treehouse Moderator 56,265 Points

I'd need to see more of your code to give you a proper answer but it could be either 1) the handler is attached to something other than the button so 'this' refers to something else in this context. 2) you're using an arrow function and arrow functions don't have their own 'this' like a regular function would.

3 Answers

Because "$(this)" refers to the button the user is clicking, which means when the user clicks to remove the "selected" class it would just loop and add the "selected" class again. This is why he selected all the other "buttons" "$('button').removeClass("selected");" to have their class removed when the user clicks another button.

I just came across this question as I was doing the video. Sorry for the late response. Hope it helped.

Ilya Chekharin
Ilya Chekharin
6,341 Points

Sorry for the late reply, I added the full code above.

Efrén Pastor
Efrén Pastor
3,140 Points

I need to see the full code but I'm sure the context of 'this' is not button, you need to understand the concept of scope and how it works on your function.