阻止方法有三种：

1、event.stopPropagation();

document.querySelector("#login").addEventListener("click",(event)=>{
	event.stopPropagation();
})

2、return false;

document.querySelector("#login").addEventListener("click",(event)=>{
	return false;
})

3、event.preventDefault();

document.querySelector("#login").addEventListener("click",(event)=>{
	event.preventDefault();
})

实例

<div id="onlogin">登录</div>
<div id="login" class="layout_login">
	<div class="layout_login_">
		<div class="layout_login_title">
			用户登录
		</div>
		<div class="layout_login_input">
			<input type="" name="" id="" placeholder="账号" value="" />
			<input type="" name="" id="" placeholder="密码" value="" />
		</div>
		
		<div class="layout_login_btn">
			登录
		</div>
	</div>
</div>
<script>
	//登录显示
	document.getElementById("onlogin").addEventListener("click",()=>{
		document.querySelector("#login").style.display = "flex"
	})
	//隐藏弹窗
	document.querySelector(".layout_login").addEventListener("click",()=>{
		document.querySelector(".layout_login").style.display = "none"
	})
	//禁止冒泡
	document.querySelector(".layout_login_").addEventListener("click",(event)=>{
		event.stopPropagation();
	})
</script>
<style>
.layout_login{
	width: 100%;
	height: 100%;
	position: fixed;
	top: 0;
	left: 0;
	background: rgba(0,0,0,0.4);
	z-index: 999;
	display: flex;
	align-items: center;
	justify-content: center;
	display: none;
}
.layout_login_{
	width: 350px;
	height: 300px;
	border-radius: 7px;
	background: #ffffff;
	padding: 20px;
}
.layout_login_title{
	font-weight: 600;
	font-size: 18px;
}
.layout_login_input{
	width: 100%;
	height: 84px;
	border-radius: 4px;
	border: 1px solid #eaeaea;
	margin-top: 30px;
}
.layout_login_input input{
	width: 100%;
	height: 50%;
	outline: none;
	border: none;
	padding: 0 14px;
	box-sizing: border-box;
}
.layout_login_input input:nth-child(1){
	border-bottom: 1px solid #eaeaea;
}
.layout_login_btn{
	width: 100%;
	height: 41px;
	background: #09aaff;
	border-radius: 4px;
	font-size: 16px;
	color: #fff;
	font-weight: 100;
	line-height: 41px;
	text-align: center;
	margin-top: 50px;
}
</style>