title: JavaScript based Bookmark button that fetches images
body: <p>I saw bookmark button on <a href="http://pinterest.com/about/goodies/" rel="nofollow">http://pinterest.com/about/goodies/</a> which list all big images or videos on the page.</p>
  
  <p>I checked out the source code and found out that the bookmark button consist of JavaScripts. </p>
  
  <p>What is the term that describes this functionality?</p>
  
  <p>Is there any documentation or good tutorial that explains creating that kind of bookmark button?</p>
  
  <p>I will appreciate your help.</p>