<script src='http://dev.sencha.com/deploy/ext-4.0.7-gpl/ext-all.js'></script>
<script>
Ext.util.Cookies.set("xxxxx", Ext.JSON.encode({
'test1':'Ура все ',
'test2':'сдохнут в конце ',
'test3':2012
}));
var val = Ext.JSON.decode(Ext.util.Cookies.get("xxxxx"));
alert (val.test1+val.test2+val.test3);
</script>