twitter's scrolling bar effect

Question

Did you notice the scrolling trend bar on twitter home page.

What is the right way to do it with jquery? I hear jquery is better than javascript.

Answer 1

If you take a look at the source code, you can see the basic structure:

<div>
  <div>
    <ul>
      <li>Year Without Rain</li>
      <li>Gameday</li>
      <li>etc...</li>
    </ul>
  </div>
  <span class="fade fade-left">&nbsp;</span>
  <span class="fade fade-right">&nbsp;</span> 
</div>

The ul element is the list container containing the topics. The position of this element is animated to scroll it. When the scrolling list is about to come to the end, the contents of the list are appended to the end of the list (to simulate the list coming around and scrolling continuously). If this wasn't done, Twitter would probably have chosen to reverse the direction of the scroll. But how they did it is much nicer.

To get the fading effect, the .fade-left and .fade-right elements are used. They are aligned to the left and right, respectably. They are set to be transparent and the image itself is a transparent gradient: http://s.twimg.com/a/1283564528/images/fronts/fade-trends2.png. Using z-index, it is positioned over the scrolling list, thus giving a transparent effect on both sides.

Twitter does indeed use jQuery (but just so you know, jQuery is JavaScript, just a JavaScript framework) and I haven't taken the time to analyze the code, but it should be pretty straight forward to implement.

Answer 2

many options:

http://stackoverflow.com/questions/41027/whats-a-good-bit-of-js-or-jquery-for-horizontally-scrolling-news-ticker