實踐課__幻燈片模式切換

時間 2019-11-30
標籤實踐幻燈片模式切換简体版
原文原文鏈接
<!DOCTYPE HTML>
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
		<title>幻燈片切換效果</title>
		<style>
			p {margin: 0;}
			body {text-align: center;}
			#box {width: 400px; height: 400px; border: 10px solid #ccc; margin: 50px auto 0; position: relative;}
			a {width: 40px; height: 40px; background: #fff; filter: 		alpha(opacity: 80); opacity: 0.8; position: absolute; top: 160px;
				font-size: 18px; color: #000; text-align: center; line-height: 40px; text-decoration: none;}
			a:hover {filter: alpha(opacity: 30); opacity: 0.3;}
			#prev {left: 10px;}
			#next {right: 10px;}
			#p1 {width: 400px; height: 30px; line-height: 30px; text-align: center; background: #000;
				  color: #fff; font-size: 14px; filter: alpha(opacity: 80); opacity: 0.8; position: absolute; bottom: 0; left: 0;}
			strong {width: 400px; height: 30px; line-height: 30px; text-align: center; background: #000; color: #fff;
				    font-size: 14px; filter: alpha(opacity: 80); opacity: 0.8; position: absolute; top: 0; left: 0;}
			#img1 {width: 400px; height: 400px;}
			span {position: absolute; width: 400px; height: 30px; line-height: 30px; text-align: center; 
				  top: -50px; left: 0; font-family: '微軟雅黑';}
		</style>
		<script>
			window.onload = function() {
				var oPrev = document.getElementById('prev');
				var oNext = document.getElementById('next');
				var oP = document.getElementById('p1');
				var oStrong = document.getElementById('strong1');
				var oImg = document.getElementById('img1');
				var aBtn = document.getElementsByTagName('input');

				var arrUrl = ['img/2_1.jpg', 'img/2_2.jpg', 'img/2_3.jpg', 'img/2_4.jpg'];
				var arrText = ['文字一', '文字二', '文字三', '識文斷字'];
				var num = 0;
				var onOff = true;

				aBtn[0].onclick = function() {
					onOff = true;
					document.getElementsByTagName('span')[0].innerHTML = '圖片可從最後一張跳轉到第一張循環切換';
				};
				
				aBtn[1].onclick = function() {
					onOff = false;
					document.getElementsByTagName('span')[0].innerHTML = '圖片只能到最後一張\或只能到第一張切換';
				};

				// 初始化
				function fnTab() {
					oP.innerHTML = arrText[num];
					oStrong.innerHTML = num + 1 + ' / ' + arrText.length;
					oImg.src = arrUrl[num];
				}
				fnTab();

				oPrev.onclick = function() {
					num--;
					if(num == -1) {
						if(onOff) {
							num = arrText.length - 1;
						} else {
							alert('這已是第一張了，不能再往前了~~');
							num = 0;
						}
						//num = arrText.length-1;
					}
					fnTab();
				};
				
				oNext.onclick = function() {
					num++;
					if(num == arrText.length) {
						if(onOff) {
							num = 0;
						} else {
							alert('已經到最後一張啦~');
							num = arrText.length - 1;
						}
					}
					fnTab();
				};

			};
		</script>
	</head>
	<body>
		<input type="button" value="循環切換" />
		<input type="button" value="順序切換" />
		<div id="box">
			<span>圖片可從最後一張跳轉到第一張循環切換</span>
			<a id="prev" href="javascript:;"> < </a>
			<a id="next" href="javascript:;">></a>
			<p id="p1">圖片文字加載中……</p>
			<strong id="strong1">圖片數量計算中……</strong>
			<img id="img1" />
		</div>
	</body>
</html>
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