Hi, please help me. How can I create the same slider just as Nbc.com's website? I see this code but I dont figure how they do that two simultaneous layer slider?

<span data-src="http://www.nbc.com/sites/nbcunbc/files/files/styles/nbc_dynamic_slide_image/public/images/2014/4/01/2014_0328_NBCHome_SVU_Hero_FL_1.jpg?itok=cbUYBuNd" class="dynamic-lead-image" style="background-image: url(&quot;http://www.nbc.com/sites/nbcunbc/files/files/styles/nbc_dynamic_slide_image/public/images/2014/4/01/2014_0328_NBCHome_SVU_Hero_FL_1.jpg?itok=cbUYBuNd&quot;"></span>


Thanks in advance.

Sandro