JavaScript图片放大缩小还原功能实现代码
2014-01-11 10:52:48 -0500
通过Math.pow(x,y)的“幂”运算来计算大小图片放大缩小的尺寸，建议最好采用onload方式引用，可以准确读到初始图片的大小。
<script type="text/javascript"> // 放大缩小控制 var PhotoSize = { zoom: 0, // 缩放率 count: 0, // 缩放次数 cpu: 0, // 当前缩放倍数值 elem: "", // 图片节点 photoWidth: 0, // 图片初始宽度记录 photoHeight: 0, // 图片初始高度记录 init: function(){ this.elem = document.getElementById("focusphoto"); this.photoWidth = this.elem.scrollWidth; this.photoHeight = this.elem.scrollHeight; this.zoom = 1.2; // 设置基本参数 this.count = 0; this.cpu = 1; }, action: function(x){ if(x === 0){ this.cpu = 1; this.count = 0; }else{ this.count += x; // 添加记录 this.cpu = Math.pow(this.zoom, this.count); // 任意次幂运算 }; this.elem.style.width = this.photoWidth * this.cpu +"px"; this.elem.style.height = this.photoHeight * this.cpu +"px"; } }; // 启动放大缩小效果 用onload方式加载，防止第一次点击获取不到图片的宽高 window.onload = function(){PhotoSize.init()}; </script> <img id="focusphoto" src="http://files.jb51.net/upload/201107/20110713233007487.jpg" /> <div> <input type="button" value="放大" onclick="PhotoSize.action(1);" /> <input type="button" value="缩小" onclick="PhotoSize.action(-1);" /> <input type="button" value="还原大小" onclick="PhotoSize.action(0);" /> <input type="button" value="查看当前倍数" onclick="alert(PhotoSize.cpu);" /></div>
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