js本地图片预览,兼容ie[6-9]、火狐、Chrome17+、Opera11+、Maxthon3

//js本地图片预览,兼容ie[6-9]、火狐、Chrome17+、Opera11+、Maxthon3

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title></title>
</head>
<body>

    <div id="divPreview">
        <img id="imgHeadPhoto" src="" alt="" />
    </div>
    <input type="file" onchange="PreviewImage(this,'imgHeadPhoto','divPreview')" size="20" />

    <script type="text/javascript">

        //js本地图片预览,兼容ie[6-9]、火狐、Chrome17+、Opera11+、Maxthon3
        function PreviewImage(fileObj, imgPreviewId, divPreviewId) {
            var allowExtention = ".jpg,.bmp,.gif,.png";//允许上传文件的后缀名document.getElementById("hfAllowPicSuffix").value;
            
            var extention = fileObj.value.substring(fileObj.value.lastIndexOf(".") + 1).toLowerCase();

            var browserVersion = window.navigator.userAgent.toUpperCase();
            
            if (allowExtention.indexOf(extention) > -1) {
                //console.log(fileObj.files);
                if (fileObj.files) {//HTML5实现预览,兼容chrome、火狐7+等
                    console.log(window.FileReader);
                    if (window.FileReader) {
                        var reader = new FileReader();
                        reader.onload = function (e) {
                            console.log(e);
                            document.getElementById(imgPreviewId).setAttribute("src", e.target.result);
                        }
                        reader.readAsDataURL(fileObj.files[0]);
                    } else if (browserVersion.indexOf("SAFARI") > -1) {
                        alert("不支持Safari6.0以下浏览器的图片预览!");
                    }
                } else if (browserVersion.indexOf("MSIE") > -1) {
                    console.log(111111);
                    if (browserVersion.indexOf("MSIE 6") > -1) {//ie6
                        document.getElementById(imgPreviewId).setAttribute("src", fileObj.value);
                    } else {//ie[7-9]
                        fileObj.select();
                        if (browserVersion.indexOf("MSIE 9") > -1)
                            fileObj.blur();//不加上document.selection.createRange().text在ie9会拒绝访问
                        var newPreview = document.getElementById(divPreviewId + "New");
                        if (newPreview == null) {
                            newPreview = document.createElement("div");
                            newPreview.setAttribute("id", divPreviewId + "New");
                            newPreview.style.width = document.getElementById(imgPreviewId).width + "px";
                            newPreview.style.height = document.getElementById(imgPreviewId).height + "px";
                            newPreview.style.border = "solid 1px #d2e2e2";
                        }
                        newPreview.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod='scale',src='" + document.selection.createRange().text + "')";
                        var tempDivPreview = document.getElementById(divPreviewId);
                        tempDivPreview.parentNode.insertBefore(newPreview, tempDivPreview);
                        tempDivPreview.style.display = "none";
                    }
                } else if (browserVersion.indexOf("FIREFOX") > -1) {//firefox
                    var firefoxVersion = parseFloat(browserVersion.toLowerCase().match(/firefox/([d.]+)/)[1]);
                    if (firefoxVersion < 7) {//firefox7以下版本
                        document.getElementById(imgPreviewId).setAttribute("src", fileObj.files[0].getAsDataURL());
                    } else {//firefox7.0+
                        document.getElementById(imgPreviewId).setAttribute("src", window.URL.createObjectURL(fileObj.files[0]));
                    }
                } else {
                    document.getElementById(imgPreviewId).setAttribute("src", fileObj.value);
                }
            } else {
                alert("仅支持" + allowExtention + "为后缀名的文件!");
                fileObj.value = "";//清空选中文件
                if (browserVersion.indexOf("MSIE") > -1) {
                    fileObj.select();
                    document.selection.clear();
                }
                fileObj.outerHTML = fileObj.outerHTML;
            }
        }
    </script>
</body>
</html>
原文地址:https://www.cnblogs.com/wolfocme110/p/5016745.html