JSFiddle - React, Tailwind, and code Playground

HTML

<div id=A1>
        <div class=b1>按</div>
        <div class=b2>按</div>
</div>

CSS

#A1 {
    background-color: #dfdfdf;
    padding: 5px;
}
.b1 {
    background-color: green;
    width: 50px;
    height: 50px;
    margin: 10px auto;
}
.b2 {
    background-color: red;
    width: 50px;
    height: 50px;
    margin: 10px auto;
}

JavaScript

var flag = false;
$(document).click(function(){
    if(flag){
        flag = false;
        return false;
    }else{
        $(".b1").fadeOut(500);
        flag = false;
    }
});

$(".b2").bind('click', function(){
    flag = true;
});