function initFbAuth(callback) {
	//suppose FB should be already initialized
	window.universalFbInit()
	FB.login(function(result){
		if (result.session) {
			if (result.perms && result.perms.indexOf('read_stream') != -1 &&
				result.perms.indexOf('publish_stream') != -1 &&
				result.perms.indexOf('offline_access') != -1) {
				
				new Ajax.Request(fbAuthorizationUrl, {
					parameters: 'uid='+result.session.uid,
					onComplete: function(t) {
						result = false
						if (t.responseText == 'ok') {
							result = true
						}
						if (typeof callback == 'function') {
							callback(result)
						}
					}
				})
			} else {
				if (typeof callback == 'function') {
					callback(false)
				}
			}
		} else {
			if (typeof callback == 'function') {
				callback(false)
			}
		}
	}, {perms:'read_stream,publish_stream,offline_access'})
}