<a href="#">TIKLA</a>

<span>YÜKLENİYOR</span>
<p>asd<(p>

a{display: inline-block; background: #00FF99; padding:20px; border-bottom:4px solid #00CC00; color:#00CC99; text-decoration:none; margin-bottom:20px;}
span{display:block; font-size:30px;}
p{display:none;}

$(document).ajaxStart(function(){
        $("span").css("display", "block");
 });
$(document).ajaxComplete(function(){
        $("span").css("display", "none");
 });