Guitar Chord Diagrams

Enter a chord name:
以下はセキュリティ脆弱性を考慮し、JavaScriptのevalや他のサイトへの遷移、リダイレクトを行わないコード例です。また、ランダムなギタージョークを表示するようにしました。

```html
<!DOCTYPE html>
<html>
<head>
	<title>Guitar Chord Diagrams</title>
	<meta charset="utf-8">
	<style>
		.container {
			display: flex;
			flex-direction: row;
			flex-wrap: wrap;
			justify-content: space-around;
			align-items: center;
		}

		.image {
			max-width: 300px;
			margin: 10px;
		}
	</style>
</head>
<body>
	<h1>Guitar Chord Diagrams</h1>
	
	<label for="chord">Enter a chord name:</label>
	<input type="text" id="chord" name="chord">
	<button onclick="showChord()">Show chord</button>

	<div class="container" id="images"></div>

	<script>
		function showChord() {
			const chord = document.getElementById("chord").value.toLowerCase();
			const url = `https://www.google.com/search?q=${chord}+chord+diagram&tbm=isch`;
			const xhr = new XMLHttpRequest();
			xhr.open("GET", url);

			xhr.onload = function() {
				if (xhr.status === 200) {
					const parser = new DOMParser();
					const html = parser.parseFromString(xhr.responseText, "text/html");
					const images = [];
					const maxImages = 5;

					// Get up to maxImages images from the search results
					html.querySelectorAll("img").forEach(img => {
						if (img.parentElement.tagName === "A" && images.length < maxImages) {
							const imgUrl = img.parentElement.href;
							images.push(imgUrl);
						}
					});

					if (images.length > 0) {
						const container = document.getElementById("images");
						container.innerHTML = "";

						images.forEach(imgUrl => {
							const img = document.createElement("img");
							img.src = imgUrl;
							img.classList.add("image");
							container.appendChild(img);
						});
					} else {
						alert("Could not find any chord diagram images.");
					}
				} else {
					alert("Could not load chord diagram images.");
				}
			};

			xhr.send();
		}

		const jokes = [
			"What do you call a guitar player without a girlfriend? Homeless.",
			"Why did the guitarist go to jail? For fingering a minor.",
			"How many guitar players does it take to change a light bulb? Ten. One to change the bulb and nine to stand around saying 'I could do that.'",
			"What do you call a guitarist who has just broken up with his girlfriend? Homeless.",
			"What do you call a guitar player who only knows two chords? A music critic.",
			"Why did the guitar teacher get arrested? For fingering A minor."
		];

		const jokeIndex = Math.floor(Math.random() * jokes.length);
		const joke = jokes[jokeIndex];

		console.log(joke);
	</script>
</body>
</html>
```

このコードは、Google検索を使って与えられたコードの画像を取得します。取得した画像は最大5枚まで表示されます。また、ランダムなジョークがコンソールに表示されます。画面に表示する場合は、適宜 `document.write` などの関数を使って表示してください。