window.innerHeight属于BOM（浏览器对象模型）,获取的高度包含横向滚动条
document.documentElement.clientHeight属于文档对象模型,不包含横向滚动条
document.body.clientHeight属于文档对象模型,body高度，如果设置body height=100%，document.documentElement.clientHeight=document.body.clientHeight
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
html,body{
margin: ;
padding: ;
height: %;
width: %;
}
.box{
height: %;
width: %;
background-color: red;
}
</style>
</head>
<body>
<div class="box"></div>
<script>
console.log('innerHeight:'+ window.innerHeight)
console.log('documentElement.clientHeight:'+ document.documentElement.clientHeight)
console.log('body.clientHeight:'+ document.body.clientHeight)
</script></body>
</html>
