<input v-fk="{set:alertMethod}">
    
    <script type="text/javascript">
    ...
        data:{
    a=" ",
    },
         methods:{
                    alertMethod:function (x) {
                        alert(x);
                        this.a=x;
                    },
                    },
                     // 自定义指令
        directives:{
                    fk(el,bindings){
                        el.onclick = function () {
                            debugger;
                            bindings.value.set(1);
                        }
                    }
                }
</script>

结果:
弹框(1)