this is my code:

Code:
Ext.regModel('UserTask', {
    fields: ['ret_code', 'ret_desc'],
proxy:{
type:'ajax',
        url: 'http://localhost/api.php',
reader: 'json'
    },

});

var user3=Ext.ModelMgr.getModel('UserTask');
user3.load(null, {
    success: function(record, operation) {
        console.log(record);
        console.log(operation);
    }
});
remote server response text is :
{"ret_code":"SUCC","ret_desc":"","task":"abc"}


the result return is :
record is undefined