css3：如何将高度100％放在静态/相对（无绝对定位）div上？(css3 : how to put height 100% on a static/relative (no absolute po

我有一个容器和2个div：1个标题（如果我添加一些行，它的高度应该是空闲的）和userList。 我希望userList具有容器的高度：任何想法如何？ （没有JS解决方案，如果没有位置则更好：使用asbolute）

#container {
	width: 300px;
	height:400px;
	background-color: #FF0000;
}
#header{
	background-color: #FFF500;
}
#userList {
	background-color: #00FF00;
	width:290px;
	height: 100%;
	overflow-y:auto;
} 
  
<div id="container">
	<div id="header">line1<br>line2<br>line3</div>
    <div id="userList">
    	line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>
        line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>
            </div>
</div> 
  
 
I have a container and 2 divs inside: 1 header (whose height should be free if I add some lines) and an userList. I want the userList to have the height of the container : any idea how ? (no JS solution, better if no position: asbolute used)
 
 
 
  
  
#container {
	width: 300px;
	height:400px;
	background-color: #FF0000;
}
#header{
	background-color: #FFF500;
}
#userList {
	background-color: #00FF00;
	width:290px;
	height: 100%;
	overflow-y:auto;
} 
  
<div id="container">
	<div id="header">line1<br>line2<br>line3</div>
    <div id="userList">
    	line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>
        line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>line<br>
            </div>
</div>