Ext.create('Ext.form.Panel', {
renderTo: Ext.getBody(),
width: 300,
bodyPadding: 10,
title: 'Dates',
items: [{
xtype: 'datefield',
anchor: '100%',
fieldLabel: 'From',
name: 'from_date',
disabledDates: ['../02/..',
'../03/..',
'../04/..',
'../05/..',
'../06/..',
'../07/..',
'../08/..',
'../09/..',
'../10/..',
'../11/..',
'../12/..',
'../13/..',
'../14/..',
'../15/..',
'../16/..',
'../17/..',
'../18/..',
'../19/..',
'../20/..',
'../21/..',
'../22/..',
'../23/..',
'../24/..',
'../25/..',
'../26/..',
'../27/..',
'../28/..',
'../29/..',
'../30/..',
'../31/..'],
maxValue: new Date() // limited to the current date or prior
}]
});
<link href="http://cdn.sencha.com/ext/gpl/4.2.0/resources/css/ext-all.css" rel="stylesheet"/>
<script src="//cdn.sencha.io/ext-4.2.0-gpl/ext-all.js"></script>