mui.alert执行问题

<script type="text/javascript">
mui.init();
mui.plusReady(function(){
require(["sps/Main","dojo","dojo/domReady!"],function(sps,dojo){
sps.InitApp().then(function(){
//plus.nativeUI.alert(,)
mui.alert("调用成功2","提示2","确认2",null);
mui.alert("调用成功1","提示1","确认1",null);
});
});
});
</script>

为何会先走“调用成功1”，然后走“调用成功2”