.prevent prevents the default event
.stop prevents the event from bubbling
.capture triggers the current event handler in capture mode
.once bound events can only be triggered once
.self triggers the event handler only when event.target is the current element itself
.charAt Take out the value corresponding to the index value from the string
v-model:
.number converts the user's input value to a numeric type
.trim filters the leading and trailing blank characters entered by the user
.lazy is updated when the change is not an input event