itochan/ex05-1.html

## ex05-1.html
<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title>演習5-1 配列操作とHTMLの一括操作</title>
        <script src="ex05-1.js"></script>
    </head>
    <body>
        <input type="button" value="数える" onclick="countElements();">
        <input type="button" value="倍" onclick="doubleElements();">
        <ol id="list">
            <li>liタグだよ</li>
        </ol>
    </body>
</html>

## ex05-1.js
function countElements() {
    var elements = document.getElementsByTagName("li");
    alert(elements.length);
}

function doubleElements() {
    var elements = document.getElementsByTagName("li");
    var length = elements.length;
    var list = document.getElementById("list");
    var element = "<li>liタグだよ</li>";
    list.innerHTML = "";
    for(var i = 0; i < length * 2; i++) {
        list.innerHTML += element;
    }
}
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<title>演習5-1 配列操作とHTMLの一括操作</title>
	<script src="ex05-1.js"></script>
	</head>
	<body>
	<input type="button" value="数える" onclick="countElements();">
	<input type="button" value="倍" onclick="doubleElements();">
	<ol id="list">
	<li>liタグだよ</li>
	</ol>
	</body>
	</html>
	function countElements() {
	var elements = document.getElementsByTagName("li");
	alert(elements.length);
	}

	function doubleElements() {
	var elements = document.getElementsByTagName("li");
	var length = elements.length;
	var list = document.getElementById("list");
	var element = "<li>liタグだよ</li>";
	list.innerHTML = "";
	for(var i = 0; i < length * 2; i++) {
	list.innerHTML += element;
	}
	}