求推荐！！！通过JS实现File上传预览功能

赢友网络 2013-12-21 10:13:35

这个东西是很多人需要的，通过file文件选择图片预览功能，

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html>

<head>

    <title></title>

</head>

<body>

    <div id="divPreview">

        <img id="imgHeadPhoto" src="noperson.jpg" style="width: 160px; height: 170px; border: solid 1px #d2e2e2;"

            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) {

                if (fileObj.files) {//HTML5实现预览，兼容chrome、火狐7+等

                    if (window.FileReader) {

                        var reader = new FileReader();

                        reader.onload = function (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) {

                    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;

            }

            return fileObj.value;    //返回路径

        }

    </script>

</body>

</html>