// vertical positioning in the viewport

(function($){

  $.fn.vCenter = function(options) {

    var pos = {

      sTop : function() {

        return window.pageYOffset || document.documentElement && document.documentElement.scrollTop 

||	document.body.scrollTop;

      },

      wHeight : function() { 

        return window.innerHeight || document.documentElement && document.documentElement.clientHeight

 || document.body.clientHeight;

      }

    };

    return this.each(function(index) {

      if (index == 0) {

        var $this = $(this);

        var elHeight = $this.height();

		    var elTop = pos.sTop() + (pos.wHeight() / 2) - (elHeight / 2);

        $this.css({

          position: 'absolute',

          marginTop: '0',

          top: elTop

        });

      }

    });

  };

})(jQuery);