propsData 选项 全局扩展的数据传递

<div id="app">
            <register></register>
 </div>

var regi = Vue.extend({

         template:`<div><h2>{{message}}--{{a}}</h2></div>`,

         data:function(){
            return{
                message:"propsData选项用于全局扩展时进行数据传递"
            }
         },
         props:["a"]
    });
  new regi({propsData:{a:123}}).$mount("register")