// This runs when the page is fully loaded
jQuery(window).load(function() {
  centerElements();
}); 

function centerElements() {
  var cHeight = 0;
  var pHeight = 0;
  var offset = 0;
  $(".valign_middle").each(function(i){
    cHeight = $(this).height();
    pHeight = $(this).parent().height();
    offset = (pHeight/2 - cHeight/2);
    $(this).css({ "position":"relative", "top":offset });
  }); 
}