Remember the problem of using Vue once. The page console prompts, error in mounted hook: typeerror: invalid SRC type
the reason is that mounted mounts unused methods. Delete them.

<template>
	<button v-on:click ="add()">add</button>
	<button v-on:click ="edit()">edit</button>
</template>

<script>
...
mounted:function(){ 
    this.select();
	//this.del();  Delete the superfluous codes
},
methods:{
  select(){
  },
  add(){
  },
  edit(){
  }
}
</script>