$(document).ready(function() {
    var zIndexNumber = 100;
    // Put your target element(s) in the selector below!
    $(".baner_top").each(function() {
        $(this).css('zIndex', zIndexNumber);
        zIndexNumber -= 10;
    });
    $(".referencje img").mouseover( function (){
        $(this).css('width','98px');
    });
    $(".referencje img").mouseout( function (){
        $(this).css('width','100px');
    });
    $('.blank').attr("target", "_blank");
});