<!DOCTYPE html>
<style>
#a {
width:50px;
height:50px;
float: left;
background: green;
}
</style>
<p>There should be a green <em>square</em> below.</p>
<div>
<div id="a"></div>
</div>
<!DOCTYPE html>
<style>
#a {
width:50px;
height:50px;
float: left;
background: green;
}
</style>
<p>There should be a green <em>square</em> below.</p>
<div>
<div id="a"></div>
</div>