include question

Hi ! I'm using include() function to print html code nested in a function in the included file when a link is selected. I was wondering if the whole php file that is included gets loaded, or the server just sends the code from desired finction? Can I put more than one function full of html code in one file without fear that each time user will have to wait for the whole php to load ? exp: if(){ include("file.php")//is the whole file.php loaded, or just the function() ? function_with_html_code_in_it(); } Thanks Nikola