//get the closable setting value.
var closable = alertify.alert().setting('closable');
//grab the dialog instance using its parameter-less constructor then set multiple settings at once.
alertify.alert()
.setting({
'label':'Agree',
'message': 'This dialog is : ' + (closable ? ' ' : ' not ') + 'closable.' ,
'onok': function(){ alertify.success('Great');}
}).show();