Ajax reload of block on an event
To answer my own question below is the correct js file that is working.

(attach:function ($) {Drupal.behaviors.my_module = {function (context){
    $('a#NextTipLink').click(function(){
        var nextTip = function(data){
            $("#divTip").html(data.nexttip);
        }
        $.ajax({
            type:'POST',
            url:this.href,
            success:nextTip,
            data: 'js=1',
            dataType:'json',
        });
        return false;
    });

}};})(jQuery);