<!DOCTYPE html>
<html>
<head>
<style type="text/css">
    body { margin: 0px; }
    div { 
        box-sizing: border-box;
        border: 1px solid black;
    }
    #left {
        float:left;
        width: 90px;
        height: 190px;
    }
    #right {
        float:right;
        width: 90px;
        height: 190px;
    }
</style>
</head>
<body>
    <div id=left></div>
    <div id=right></div>
</body>
</html>