原生JavaScript实现的简单放大镜效果示例
本文实例讲述了原生JavaScript实现的简单放大镜效果。分享给大家供大家参考,具体如下:
原理: 其实所谓的放大就是准备两张一样的图片,除大小不一样。鼠标移动到不同位置,将会显示大图片对应的图片内容。
完整代码:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>放大镜效果</title> </head> <body> <div id="wrap" style="position: relative;width: 900px;margin: 0 auto;text-align: center;"> <div id="smallImg" style="width: 400px;height: 400px; position: relative;z-index: 1;"> <img src="small.jpg" style="width: 400px;height: 400px;"/> <span id="filter" style="width: 200px;height: 200px;background-color: blue;opacity: 0.1;position: absolute;top: 0;left: 0; z-index: 2;cursor: move;display: none;"> <span> </div> <div id="bigImg" style="width: 400px;height: 400px;overflow: hidden;position: absolute;right: 0px;top: 0;display: none;"> <img src="large.jpg" style="width: 800px;height:800px; position: absolute;left: 0;top: 0;"> </div> </div> <script type="text/javascript"> var filter = document.getElementById('filter'); var smallImg = document.getElementById('smallImg'); var bigImg = document.getElementById('bigImg'); var wrap = document.getElementById('wrap'); var largeImgs = bigImg.getElementsByTagName('img')[0]; smallImg.onmouseover = function(){ bigImg.style.display = "inline-block"; filter.style.display = "inline-block"; } smallImg.onmousemove = function(event){ var event = event || window.event; var mouseleft = event.clientX - wrap.offsetLeft; var mousetop = event.clientY - wrap.offsetTop; var left = mouseleft<smallImg.offsetWidth/4?0:mouseleft>smallImg.offsetWidth*3/4?smallImg.offsetWidth/2:(mouseleft - filter.offsetWidth/2); var top = mousetop<smallImg.offsetHeight/4?0:mousetop>smallImg.offsetHeight*3/4?smallImg.offsetHeight/2:(mousetop - filter.offsetWidth/2); filter.style.left = left + "px"; filter.style.top = top +"px"; largeImgs.style.left = "-" + left*bigImg.offsetWidth/smallImg.offsetWidth + "px"; largeImgs.style.top = "-" + top*bigImg.offsetHeight/smallImg.offsetHeight + "px"; } smallImg.onmouseout = function(){ bigImg.style.display = "none"; filter.style.display = "none"; } </script> </body> </html>
运行效果:
更多关于JavaScript相关内容感兴趣的读者可查看本站专题:《JavaScript图片操作技巧大全》、《JavaScript图形绘制技巧总结》、《JavaScript页面元素操作技巧总结》、《JavaScript事件相关操作与技巧大全》、《JavaScript数据结构与算法技巧总结》及《JavaScript数学运算用法总结》
希望本文所述对大家JavaScript程序设计有所帮助。
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