EXT.JS以下两种写法在初始载入时是一样的效果

/*
Ext.application({
    name: 'MyfirstApplication',
    launch: function () {
        Ext.Msg.alert("Hello", "My first App!");
    }
});
*/
Ext.onReady(function () {
    //alert("This is my first Extjs app !");
    //Ext.Msg.alert("Alert", "This is my first Ext js app !");
    Ext.Msg.confirm("Confirm","Do you like Ext JS 5?",
                   function(btn){
        if (btn == "yes"){
            Ext.Msg.alert("Great", "This is my first Ext js app !");
        } else {
            Ext.Msg.alert("Really", "Too Bad!");
        }
    });
});