function alert_popup (msg, alignment) {

	var width = 300;
	var height = 150;
	var top_offset = 50; // top bars
	var width_offset = 10; // scrollbar
	if (alignment=='') alignment='center';

	var top = (screen.height/2)-(height/2)-top_offset;
	var left = (screen.width/2)-(width/2)-width_offset;

	var msg_html = '<html><body bgcolor="#EEEEEE"><form><p align="' + alignment + '"><font face="Arial" size="2">' + msg + '</font><br></p><p align="center"><input type="button" value="    OK    " onclick="window.close()"></p></form></body></html>';

	var popup = window.open('','','top=' + top + ',left=' + left + ',screenY=' + top + ',screenX=' + left +',width=' + width + ',height=' + height + ',dependent,resizable,scrollbars');
	popup.document.write(msg_html);
	popup.focus();

}

function center_popup(popup_url, popup_width, popup_height, popup_top_offset, popup_options) {

	// Position des Fensters berechnen
	var posx = (screen.availWidth - popup_width)/2;

	// offset wird z.B. wegen toolbar-Höhe abgezogen.
	var posy=(screen.availHeight - popup_height)/2-popup_top_offset;

	// Beistrich anfügen
	if (popup_options!='') popup_options = popup_options + ',';

	// Fenster öffnen und Fokus holen
	popup=window.open(popup_url,'',popup_options + 'width=' + popup_width + ',height=' + popup_height + ',screenX=' + posx+ ',screenY=' + posy + ',left=' + posx + ',top=' + posy + '');
	popup.focus();
	return(popup);
}


function setClassIfNotSelected(element_id, classname) {
	var elementToDisplay = document.getElementById(element_id);
 	if (elementToDisplay.className.indexOf('_selected')==-1) {
		elementToDisplay.className = classname;
	}
}

function setClass( element_id , classname) {
	var elementToDisplay = document.getElementById( element_id );
	elementToDisplay.className = classname;
}

function selectButton (group_id, index, totalButtonCount, classname_default, classname_selected) {
	for (i = 1; i <= totalButtonCount; i++) {
		setClass(group_id + i , classname_default);
	}

	setClass(group_id + index, classname_selected);
}


function clearButtons (group_id, index, totalButtonCount, classname_default) {
	for (i = 1; i <= totalButtonCount; i++) {
		setClass(group_id + i , classname_default);
	}

}


function toggleButton (form, fieldname, buttonid, classname_default, classname_selected) {
	if (form[fieldname].value=='') {
	 	form[fieldname].value = '1';
	 	setClass(buttonid, classname_selected);
	} else {
		form[fieldname].value = '';
	 	setClass(buttonid, classname_default);
	}

}
