function openvenster(url,popup_width,popup_height,scrollbars) {
	var undefined;
	if (popup_width == undefined) popup_width=800;
	if (popup_height == undefined) popup_height=600;
	if (scrollbars == undefined) scrollbars='no';
	left_pos = (screen.availWidth/2) - (popup_width / 2);
	top_pos = (screen.availHeight/2) - (popup_height / 2);
	mywin = window.open(url,'popup','height=' + popup_height + ',left=' + left_pos + ',top=' +top_pos + ',width=' + popup_width + ',scrollbars=' + scrollbars);
	mywin.focus();
}

function watersportcatalogus() {
	openvenster("http://theboardroom.turnpages.nl/");
}
function viewimage(image) {
	openvenster('/include/php/image.php?img=' + image);
}
addWindowOnload = function( f ) {
  var current = window.onload; 
  if( typeof window.onload != 'function' ) {
    window.onload = f;
  }
  else { 
  	window.onload = function() { current(); f() };
  }
}