本文实例为大家分享了javascript图片预览功能实现的具体代码，供大家参考，具体内容如下
先为大家分享一段关于js图片预览的代码，兼容火狐和谷歌浏览器
/* 案例展示图片预览 */ $(function(){ $("#file0").bind("change",function(){ clickupLoad(); }); }); function clickupLoad(){ var imgObject = document.getElementById('file0'); var getImageSrc = getFullPath(imgObject); // 本地路径 var srcs = window.URL.createObjectURL(imgObject.files[0]); var pos = getImageSrc.lastIndexOf("."); var lastname = getImageSrc.substring(pos, getImageSrc.length) // 图片后缀] if(srcs!=""){ $("#yulan2").attr("src",srcs); }else{ alert("请选择一张图片"); } } function getFullPath(obj) { //得到图片的完整路径 if (obj) { if (window.navigator.userAgent.indexOf("MSIE") >= 1){ obj.select(); return document.selection.createRange().text; }else if(window.navigator.userAgent.indexOf("Firefox") >= 1) { if (obj.files) { return window.URL.createObjectURL(obj.files[0]); } return obj.value; } return obj.value; } }
实例代码实现js上传图片及时预览：
<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>图片上传本地预览</title> <style type="text/css"> #preview{width:260px;height:190px;border:1px solid #000;overflow:hidden;} #imghead {filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=image);} </style> <script type="text/javascript"> //图片上传预览 IE是用了滤镜。 function previewImage(file) { var MAXWIDTH = 260; var MAXHEIGHT = 180; var div = document.getElementById('preview'); if (file.files && file.files[0]) { div.innerHTML ='<img id=imghead>'; var img = document.getElementById('imghead'); img.onload = function(){ var rect = clacImgZoomParam(MAXWIDTH, MAXHEIGHT, img.offsetWidth, img.offsetHeight); img.width = rect.width; img.height = rect.height; // img.style.marginLeft = rect.left+'px'; img.style.marginTop = rect.top+'px'; } var reader = new FileReader(); reader.onload = function(evt){img.src = evt.target.result;} reader.readAsDataURL(file.files[0]); } else //兼容IE { var sFilter='filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale,src="'; file.select(); var src = document.selection.createRange().text; div.innerHTML = '<img id=imghead>'; var img = document.getElementById('imghead'); img.filters.item('DXImageTransform.Microsoft.AlphaImageLoader').src = src; var rect = clacImgZoomParam(MAXWIDTH, MAXHEIGHT, img.offsetWidth, img.offsetHeight); status =('rect:'+rect.top+','+rect.left+','+rect.width+','+rect.height); div.innerHTML = "<div id=divhead+rect.width+"px;height:"+rect.height+"px;margin-top:"+rect.top+"px;"+sFilter+src+""'></div>"; } } function clacImgZoomParam( maxWidth, maxHeight, width, height ){ var param = {top:0, left:0, width:width, height:height}; if( width>maxWidth || height>maxHeight ) { rateWidth = width / maxWidth; rateHeight = height / maxHeight; if( rateWidth > rateHeight ) { param.width = maxWidth; param.height = Math.round(height / rateWidth); }else { param.width = Math.round(width / rateHeight); param.height = maxHeight; } } param.left = Math.round((maxWidth - param.width) / 2); param.top = Math.round((maxHeight - param.height) / 2); return param; } </script> </head> <body> <div id="preview"> <img id="imghead" width=100 height=100 border=0 src='<%=request.getContextPath()%>/images/defaul.jpg'> </div> <input type="file" onchange="previewImage(this)" /> </body> </html>
以上就是本文的全部内容，希望对大家学习javascript程序设计有所帮助。
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