基于vue.js中关于下拉框的值默认及绑定问题

<template>

 <select v-model='selected' @click="disable()">
 <option v-for="(option,index) in options" v-bind:value="option.value" :disabled="option.disabled">
 {{ option.text }}{{index}}{{option.disabled}}
 </option>
 </select>
 <span>Selected: {{ selected }}</span>
</template>
<script>
 export default{
 name: 'second',
 data(){
 return {
 selected: 'sex', // 这里选择默认项
 options: [
 {text: '点击选择性别', value: 'sex', disabled: ''},
 {text: '男', value: '1'},
 {text: '女', value: '2'}
 ]
 }
 },
 methods: {
 disable: function () {
 this.options[0].disabled = disabled;
 },
 }
 }
</script>