function validate_registration ()
	{
		var errors = "Voltooi onderstaande!\n";
		var post = true;
		
		if ( $('input#title').val() == "" )
		{
			errors += "Titel\n";
			post = false;
		}
		
		if ( $('textarea#intro').val() == "" )
		{
			errors += "Inleiding\n";
			post = false;
		}
		
		if ( $('textarea#detail1').val() == "" )
		{
			errors += "Beskrywing\n";
			post = false;
		}
		
		if ( post == false ) alert ( errors );
		return post;
	}
	
	function selection_changed ()
    	{
    		var age_count = $("#age_group .short_list tr.data_row").size ();
    		
    		if ( age_count > 0 )
    		{
    			$(".buttons_table .button_wrapper.add_button").removeClass ( "disabled" );
    			$(".buttons_table .button_wrapper.reset_button").removeClass ( "disabled" );
    		} else {
    			$(".buttons_table .button_wrapper.add_button").addClass ( "disabled" );
    			$(".buttons_table .button_wrapper.reset_button").addClass ( "disabled" );
            }
        }
        
	$(document).ready ( function () {
    
		$('input#filter_submit').click( function () {
				if ( validate_registration() == false )
				{
					return false;
				}
				else
				{
					$('input#filter_submit').submit();
				}
			});
		
        $.multiselect ( "#age_group", "/main/age_groups", {
				onchange: function () {
					selection_changed ();
				}
			} );
		});