afshin222

i have this problem also but when i use this code, this problem solved.

function widget_dailytopten_init() {
        if(!function_exists('register_sidebar_widget')) { return; }
        function widget_dailytopten($args) {
		echo $before_title
                      . 'My widget'
                      . $after_title;

			Hello widget!
        }
        register_sidebar_widget('My sidget','widget_dailytopten');
    }
add_action('plugins_loaded', 'widget_dailytopten_init');

Regard, Afshin.m

Hello,

I prefer http://codex.wordpress.org/Function_Reference/get_categories
You can find your question easily just by search!

Good luck!