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Last week I had to do a news carousel for a project I’m developing. It had been a while since I had the chance to do something interesting with jQuery, so I wanted to share the experience of how easily you can build similar widgets for your site.

So first let’s take a look at what we want to build.

Now, I know that there are a few plugins out there for jQuery that probably can do this, but the point of this post is to show how simple it is to create something like this with a few lines of jQuery and CSS.

Let’s begin by defining how we will organize the content. Being a list of news, we can either use an ordered or an unordered list.

<div id="news_carousel">
  <ul class="news">
    <li>
      <img src="" alt="" />
      <strong><a href="#">Title</a></strong>
      <span>Description</span>
    </li>
  </ul>
</div>

Now that we have our content, we have to style it. The keys here are to:

• Align the list elements one next to the other.
• Make #news_carousel just show one list element at a time
• Use relative and absolute positioning to show the titles and descriptions over each image

Here’s the CSS used in the sample with some comments:

 #news_carousel {
     width: 444px;
     height: 333px;
     margin: 0;
     padding: 0;
     overflow: hidden;  /* this will make only show 1 li */
     position: relative;
  }
  #news_carousel ul.news {
    list-style-type: none;
    margin: 0;
    padding: 0;
    position: relative;
  }
  #news_carousel ul li {
    margin: 0;
    padding: 0;
    position: relative; /* so that we can do absolute positioning of the paragraph inside of it */
    float: left; /* align one next to the other */
  }
  #news_carousel ul.news li p {
    position: absolute;
    bottom: 10px;
    left: 0;
    margin: 5px;
  }
  #news_carousel ul.news li p strong {
    display: block;
    padding: 5px;
    margin: 0;
    font-size: 20px;
    background: #444;
  }
  #news_carousel ul.news li p span {
    padding: 2px 5px;
    color: #000;
    background: #fff;
  }
  #news_carousel ul.controls {
    position: absolute;
    top: 0px; right: 20px;
    list-style-type: none;
  }
  #news_carousel ul.controls li a {
    float: left;
    font-size: 15px;
    margin: 5px;
    padding: 2px 7px;
    background: #000;
    text-decoration: none;
    outline: none;
  }
  #news_carousel ul.controls li a.active {
    border: 2px solid #ccc;
  }

The Javascript code is pretty self-explanatory:

var news_carousel = function() {
    var items_size = $('#news_carousel ul li').length;

    if (items_size == 0) return;

    // Calculate the total width and set that value to the ul.news width
    // Store each item width
    var width = 0;
    var widths = [];
    $('#news_carousel ul.news li img').each(function(i, e) {
      widths[i] = $(e).width();
      width += widths[i];
    });

    $("#news_carousel ul.news").width(width);

    // Append the controls
    controls = '<ul class="controls"><li><a class="active" href="#">1</a>';
    for ( var i = 2; i &lt;= items_size; i++) {
       controls += '</li><li><a href="#">' + i + '</a></li>';
    }
    controls += '</ul>';
    $('#news_carousel').append(controls);

    $('#news_carousel ul.controls li a').click(function(event) {
      // if the ul is already moving, then do nothing
      if ($("#news_carousel ul.news:animated").length &gt; 0) return false;

      var clicked_item = $(event.target);
      var current_active = $("#news_carousel ul.controls li a.active");
      var current_index = parseInt(current_active.text());
      var new_index = parseInt(clicked_item.text());
      var move = new_index - current_index; // get how many items it should be moved

      if (move != 0) {
        direction = (move &gt; 0)? "-=": "+=";
        $('#news_carousel ul.news').animate({marginLeft: direction + widths[new_index-1] }, 300);
        clicked_item.addClass("active");
        current_active.removeClass("active");
      }

      return false;
    });
  }();

And that’s it! Around 100 lines of code and you have your own home-made news carousel. Hope you found it useful!

(Pictures taken from: http://www.flickr.com/photos/christing/268490607/ and http://www.flickr.com/photos/11717181@N02/1170861540/.)