最简单的轮播效果

叁歲伎倆 2022-03-19 01:52 164阅读 0赞

<!DOCTYPE html>
    <html lang="en">
    <head>
    <meta charset="UTF-8">
    <title>最简单的轮播效果</title>
    <style>
    * { 
    	margin: 0;
    	padding: 0
    }
    
    .box { 
    	width: 500px;
    	height: 300px;
    	border: 1px solid #ccc;
    	margin: 100px auto;
    	padding: 5px;
    }
    
    .inner { 
    	width: 500px;
    	height: 300px;
    	position: relative;
    	overflow: hidden;
    }
    
    .inner img { 
    	width: 500px;
    	height: 300px;
    	vertical-align: top
    }
    
    ul { 
    	width: 1000%;
    	position: absolute;
    	list-style: none;
    	left: 0;
    	top: 0;
    }
    
    .inner li { 
    	float: left;
    }
    
    ol { 
    	position: absolute;
    	height: 20px;
    	right: 20px;
    	bottom: 20px;
    	text-align: center;
    	padding: 5px;
    }
    
    ol li { 
    	display: inline-block;
    	width: 20px;
    	height: 20px;
    	line-height: 20px;
    	background-color: #fff;
    	margin: 5px;
    	cursor: pointer;
    }
    
    ol .current { 
    	background-color: red;
    }
    
    #arr { 
    	display: none;
    }
    
    #arr span { 
    	width: 40px;
    	height: 40px;
    	position: absolute;
    	left: 5px;
    	top: 50%;
    	margin-top: -20px;
    	background: #fff;
    	cursor: pointer;
    	line-height: 40px;
    	text-align: center;
    	font-weight: bold;
    	font-family: '黑体';
    	font-size: 30px;
    	color: #000;
    	opacity: 0.5;
    	border: 1px solid #fff;
    }
    
    #arr #right { 
    	right: 5px;
    	left: auto;
    }
    </style>
    </head>
    <body>
    	<div class="box" id="box">
    		<div class="inner">
    			
    			<ul>
    				<li><a href="#"><img src="C:\Users\admin\Desktop\恒硕邮箱.png" alt=""></a></li>
    				<li><a href="#"><img src="C:\Users\admin\Desktop\2.png" alt=""></a></li>
    				<li><a href="#"><img src="C:\Users\admin\Desktop\3.png" alt=""></a></li>
    				<li><a href="#"><img src="C:\Users\admin\Desktop\4.png" alt=""></a></li>
    				<li><a href="#"><img src="C:\Users\admin\Desktop\5.png" alt=""></a></li>
    
    			</ul>
    
    			<ol class="bar">
    
    			</ol>
    			
    			<div id="arr">
    				<span id="left"> < </span> <span id="right"> > </span>
    			</div>
    
    		</div>
    	</div>
    	<script>
    		/** * * @param id 传入元素的id * @returns {HTMLElement | null} 返回标签对象，方便获取元素 */
    		function my$(id) { 
    			return document.getElementById(id);
    		}
    
    		//获取各元素，方便操作
    		var box = my$("box");
    		var inner = box.children[0];
    		var ulObj = inner.children[0];
    		var list = ulObj.children;
    		var olObj = inner.children[1];
    		var arr = my$("arr");
    		var imgWidth = inner.offsetWidth;
    		var right = my$("right");
    		var pic = 0;
    		//根据li个数，创建小按钮
    		for ( var i = 0; i < list.length; i++) { 
    			var liObj = document.createElement("li");
    
    			olObj.appendChild(liObj);
    			liObj.innerText = (i + 1);
    			liObj.setAttribute("index", i);
    
    			//为按钮注册mouseover事件
    			liObj.onmouseover = function() { 
    				//先清除所有按钮的样式
    
    				for ( var j = 0; j < olObj.children.length; j++) { 
    					olObj.children[j].removeAttribute("class");
    				}
    				this.className = "current";
    				pic = this.getAttribute("index");
    				animate(ulObj, -pic * imgWidth);
    			}
    		}
    
    		//设置ol中第一个li有背景颜色
    		olObj.children[0].className = "current";
    		//克隆一个ul中第一个li,加入到ul中的最后=====克隆
    		ulObj.appendChild(ulObj.children[0].cloneNode(true));
    
    		var timeId = setInterval(onmouseclickHandle, 1000);
    		//左右焦点实现点击切换图片功能
    		box.onmouseover = function() { 
    			arr.style.display = "block";
    			clearInterval(timeId);
    		};
    		box.onmouseout = function() { 
    			arr.style.display = "none";
    			timeId = setInterval(onmouseclickHandle, 1000);
    		};
    
    		right.onclick = onmouseclickHandle;
    		function onmouseclickHandle() { 
    			//如果pic的值是5,恰巧是ul中li的个数-1的值,此时页面显示第六个图片,而用户会认为这是第一个图,
    			//所以,如果用户再次点击按钮,用户应该看到第二个图片
    			if (pic == list.length - 1) { 
    				//如何从第6个图,跳转到第一个图
    				pic = 0;//先设置pic=0
    				ulObj.style.left = 0 + "px";//把ul的位置还原成开始的默认位置
    			}
    			pic++;//立刻设置pic加1,那么此时用户就会看到第二个图片了
    			animate(ulObj, -pic * imgWidth);//pic从0的值加1之后,pic的值是1,然后ul移动出去一个图片
    			//如果pic==5说明,此时显示第6个图(内容是第一张图片),第一个小按钮有颜色,
    			if (pic == list.length - 1) { 
    				//第五个按钮颜色干掉
    				olObj.children[olObj.children.length - 1].className = "";
    				//第一个按钮颜色设置上
    				olObj.children[0].className = "current";
    			} else { 
    				//干掉所有的小按钮的背景颜色
    				for ( var i = 0; i < olObj.children.length; i++) { 
    					olObj.children[i].removeAttribute("class");
    				}
    				olObj.children[pic].className = "current";
    			}
    		}
    		left.onclick = function() { 
    			if (pic == 0) { 
    				pic = list.length - 1;
    				ulObj.style.left = -pic * imgWidth + "px";
    			}
    			pic--;
    			animate(ulObj, -pic * imgWidth);
    			for ( var i = 0; i < olObj.children.length; i++) { 
    				olObj.children[i].removeAttribute("class");
    			}
    			//当前的pic索引对应的按钮设置颜色
    			olObj.children[pic].className = "current";
    		};
    
    		//设置任意的一个元素,移动到指定的目标位置
    		function animate(element, target) { 
    			clearInterval(element.timeId);
    			//定时器的id值存储到对象的一个属性中
    			element.timeId = setInterval(function() { 
    				//获取元素的当前的位置,数字类型
    				var current = element.offsetLeft;
    				//每次移动的距离
    				var step = 10;
    				step = current < target ? step : -step;
    				//当前移动到位置
    				current += step;
    				if (Math.abs(current - target) > Math.abs(step)) { 
    					element.style.left = current + "px";
    				} else { 
    					//清理定时器
    					clearInterval(element.timeId);
    					//直接到达目标
    					element.style.left = target + "px";
    				}
    			}, 10);
    		}
    	</script>
    </body>
    </html>

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