事件处理

<div id="example-1">
  <button v-on:click="counter += 1">Add 1</button>
  <p>The button above has been clicked {{ counter }} times.</p>
</div>

var example1 = new Vue{
  el: '#example-1',
  data: {
    counter: 0
  }
})

<div id="example-2">
  <!-- `greet` is the name of a method defined below -->
  <button v-on:click="greet">Greet</button>
</div>

var example2 = new Vue{
  el: '#example-2',
  data: {
    name: 'Vue.js'
  },
  // define methods under the `methods` object
  methods: {
    greet: function (event) {
      // `this` inside methods points to the Vue instance
      alert('Hello ' + this.name + '!')
      // `event` is the native DOM event
      if (event) {
        alert(event.target.tagName)
      }
    }
  }
})

// you can invoke methods in JavaScript too
example2.greet() // => 'Hello Vue.js!'

<div id="example-3">
  <button v-on:click="say('hi')">Say hi</button>
  <button v-on:click="say('what')">Say what</button>
</div>

new Vue{
  el: '#example-3',
  methods: {
    say: function (message) {
      alert(message)
    }
  }
})

<button v-on:click="warn('Form cannot be submitted yet.', $event)">
  Submit
</button>

// ...
methods: {
  warn: function (message, event) {
    // now we have access to the native event
    if (event) event.preventDefault()
    alert(message)
  }
}

<!-- the click event's propagation will be stopped -->
<a v-on:click.stop="doThis"></a>

<!-- the submit event will no longer reload the page -->
<form v-on:submit.prevent="onSubmit"></form>

<!-- modifiers can be chained -->
<a v-on:click.stop.prevent="doThat"></a>

<!-- just the modifier -->
<form v-on:submit.prevent></form>

<!-- use capture mode when adding the event listener -->
<!-- i.e. an event targeting an inner element is handled here before being handled by that element -->
<div v-on:click.capture="doThis">...</div>

<!-- only trigger handler if event.target is the element itself -->
<!-- i.e. not from a child element -->
<div v-on:click.self="doThat">...</div>

<!-- the click event will be triggered at most once -->
<a v-on:click.once="doThis"></a>

<!-- only call vm.submit() when the keyCode is 13 -->
<input v-on:keyup.13="submit">

<!-- same as above -->
<input v-on:keyup.enter="submit">

<!-- also works for shorthand -->
<input @keyup.enter="submit">

// enable v-on:keyup.f1
Vue.config.keyCodes.f1 = 112

<input @keyup.page-down="onPageDown">

<!-- Alt + C -->
<input @keyup.alt.67="clear">

<!-- Ctrl + Click -->
<div @click.ctrl="doSomething">Do something</div>

<!-- this will fire even if Alt or Shift is also pressed -->
<button @click.ctrl="onClick">A</button>

<!-- this will only fire when only Ctrl is pressed -->
<button @click.ctrl.exact="onCtrlClick">A</button>