/* ========================================================
*  keep a running tab of the modaility id's that have been
*  viewed in a cookie. when the Portal site is vacated
*  (window closed or different domain) pop open a window
*  with a mailform. mailform will have a hidden field that
*  contains a list of viewed modalities.
*  cookie holding the modalities is tied to the browser
*  window - when the session is dead, so is the cookie
*  ======================================================== */
function add_modality(id)
{
	id = id.toString();
	viewed = list_modalities();
	if ( viewed.inArray(id) == false ) {
		viewed.push(id);
		viewed.sort();
		setCookie( 'modalities', viewed );
		return true;
	}
	return false;
}
function list_modalities()
{
	var viewed = new Array();
	if ( getCookie('modalities') ) {
		viewed = getCookie('modalities').split(',');
	}	
	return viewed;
}
// exit window
function exit()
{
	window.open('exitform.html', 'exitform', 'toolbar=no,location=no,scrollbars=no,menubar=no,width=844,height=440,top=0,left=0');
}

/* utility functions ======================================*/
Array.prototype.inArray = function (value) {
	var i;
	for (i=0; i < this.length; i++) {
		if (this[i] === value) {
			return true;
		}
	}
	return false;
};
function getCookie( name ) {
	var start = document.cookie.indexOf( name + "=" );
	var len = start + name.length + 1;
	if ( ( !start ) && ( name != document.cookie.substring( 0, name.length ) ) ) {
		return null;
	}
	if ( start == -1 ) return null;
	var end = document.cookie.indexOf( ';', len );
	if ( end == -1 ) end = document.cookie.length;
	return unescape( document.cookie.substring( len, end ) );
};
function setCookie( name, value, expires, path, domain, secure ) {
	var today = new Date();
	today.setTime( today.getTime() );
	if ( expires ) {
		expires = expires * 1000 * 60 * 60 * 24;
	}
	var expires_date = new Date( today.getTime() + (expires) );
	document.cookie = name+'='+escape( value ) +
		( ( expires ) ? ';expires='+expires_date.toGMTString() : '' ) + 
		( ( path ) ? ';path=' + path : '' ) +
		( ( domain ) ? ';domain=' + domain : '' ) +
		( ( secure ) ? ';secure' : '' );
};
function deleteCookie( name, path, domain ) {
	if ( getCookie( name ) ) document.cookie = name + '=' +
			( ( path ) ? ';path=' + path : '') +
			( ( domain ) ? ';domain=' + domain : '' ) +
			';expires=Thu, 01-Jan-1970 00:00:01 GMT';
};