$(document).ready(function(){

     $(window).resize(function(){
          $('#footer ').css({
               position:'absolute',
               top: ($(window).height() - $('#footer ').outerHeight())
          });   
     });
     
     $(window).resize(function(){
          if($(window).height() > 700){
               $('#wrapper-header ').css({
                    position: 'absolute',
                    top: ($(window).height() - $('#footer ').outerHeight()) /6
               });
          }
     });
     

// Ejecutamos la funci—n
$(window).resize();

});