$(".delete").click(
    function()  {
        var thesender = this;
        $(thesender).text("Del...");
        $.getJSON("ajax.php", {},
            function(data) {
                if (data["result"])
                    $(thesender).remove(); // variable defined outside
                else
                    alert('Error!');
            }
        );

        return false;
    }
);

This can cause problems if user clicks on another ".delete" before the ajax callback is called?