[jQuery] chaining and functions

[jan]

Hi, another starter question:

I do not understand why

$('#content').empty().append("<b>hello</b>");

works, and this works

$('#content').empty().append(makeContent());

function makeContent(){
                return "<b>hello</b>";
                };

and this

$('#content').empty().append( function() { return "<b>hello</b>" } );

does not produce any output?

thanks, Jan Vandorpe