<div name="top">
  <!-- some code -->
  <a class="myLinkToTop" href="#bot">Click</a>
  <!-- some code -->
<div name="bot">

<script>
   $(".myLinkToTop").click(function(){
     $("a.myLinkToTop").attr("href","#top");
   });
 </script>

$(".myLinkToTop").click(function(e){
    e.preventDefault();
    window.location.href = this.href;
    this.href = this.hash === "#top" ? "#bot" : "#top";
 });

$(".myLinkToTop").on("click", function () {
    var $this = $(this), // cache "this as a jQuery object"
        href = $this.attr("href");

    if (href === "#bot") {
        setTimeout(function () {
            $this.attr("href", "#top");
        }, 100);
    } else {
        setTimeout(function () {
            $this.attr("href", "#bot");
        }, 100);
    }
});