<!DOCTYPE html>
<html>
<head>
    <style>
        @media only screen and (max-width: 480px) {
            .overflow-hidden 
            {
                overflow: hidden;
            }
            
            .float-left
            {
                float: left;
                background: #f0f;
            }
        }
    </style>
</head>
<body>
    <h1>Iframe content</h1>
    <div class="float-left">
        <textarea>This text should be visible when window is resized </textarea>

    </div>
    <div class="overflow-hidden">
        <textarea>This text should be visible when window is resized </textarea>
    </div>
</body>
</html>