Show div #id on click with jQuery

The problem you’re having is that the event-handlers are being bound before the elements are present in the DOM, if you wrap the jQuery inside of a $(document).ready() then it should work perfectly well:

$(document).ready(
    function(){
        $("#music").click(function () {
            $("#musicinfo").show("slow");
        });

    });

An alternative is to place the <script></script> at the foot of the page, so it’s encountered after the DOM has been loaded and ready.

To make the div hide again, once the #music element is clicked, simply use toggle():

$(document).ready(
    function(){
        $("#music").click(function () {
            $("#musicinfo").toggle();
        });
    });

JS Fiddle demo.

And for fading:

$(document).ready(
    function(){
        $("#music").click(function () {
            $("#musicinfo").fadeToggle();
        });
    });

JS Fiddle demo.