Vue

HTML

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

Vue

// inject a handler for `myOption` custom option
Vue.mixin({
  created: function () {
    var myOption = this.$options.myOption
    if (myOption) {
      alert(myOption)
    }
  }
})

new Vue({
  myOption: 'hello!'
})
new Vue({
  myOption: 'hello1!'
})
// => "hello!"