index.html

<!DOCTYPE html>
<html>
<head>
	<title>Browser Extension</title>
	<link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>
	<div class="container">
		<div class="form">
<!-- 			<h1>Browser Extension</h1> 	 -->
<!-- 			<label for="input">Input:</label> -->
			<textarea id="input" rows="5"></textarea>
			<div class="input-row">
				<label for="operation">Operation:</label>
				<select id="operation">
					<option value="urlencode">URL Encode</option>
					<option value="uppercase">Uppercase</option>
					<option value="lowercase">Lowercase</option>
					<option value="reverse">Reverse</option>
				</select>
				<button id="submit">Submit</button>
			</div>
<!--			<label for="output">Output:</label>  -->
			<textarea id="output" rows="5"></textarea>
		</div>
	</div>
	<script src="script.js"></script>
</body>
</html>