1、原生写法

// html

<div id="box" style="width:110px;height:110px;background-color:red"></div>

//js
document.addEventListener('click',(e)=>{
        alert('zhixing')
        var  box = document.getElementById('box');
        if(box.contains(e.target)){
            alert('在内');
        }else{
            alert('在外');        
        }
    })

2、 vue 写法

//html

<div id="box" ref="box" style="width:110px;height:110px;background-color:red"></div>

//js
created(){
    document.addEventListener('click',(e)=>{
        console.log(this.$refs.box.contains(e.target));
        if(!this.$refs.box.contains(e.target)){
            this.isShowDialog = false;
        }
    })
}