<div style="border:2px dashed red;"><p>图片上传前预览：<input type="file" id="xdaTanFileImg" οnchange="xmTanUploadImg(this)" accept="image/*"/><input type="button" value="隐藏图片" οnclick="document.getElementById('xmTanImg').style.display = 'none';"/><input type="button" value="显示图片" οnclick="document.getElementById('xmTanImg').style.display = 'block';"/></p><img id="xmTanImg"/><div id="xmTanDiv"></div></div><hr /><script type="text/javascript">            //判断浏览器是否支持FileReader接口if (typeof FileReader == 'undefined') {document.getElementById("xmTanDiv").InnerHTML = "<h1>当前浏览器不支持FileReader接口</h1>";//使选择控件不可操作document.getElementById("xdaTanFileImg").setAttribute("disabled", "disabled");}//选择图片，马上预览function xmTanUploadImg(obj) {var file = obj.files[0];console.log(obj);console.log(file);console.log("file.size = " + file.size);  //file.size 单位为bytevar reader = new FileReader();//读取文件过程方法reader.onloadstart = function (e) {console.log("开始读取....");}reader.onprogress = function (e) {console.log("正在读取中....");}reader.onabort = function (e) {console.log("中断读取....");}reader.onerror = function (e) {console.log("读取异常....");}reader.onload = function (e) {console.log("成功读取....");var img = document.getElementById("xmTanImg");img.src = e.target.result;//或者 img.src = this.result;  //e.target == this}reader.readAsDataURL(file)}</script>

<script type="text/javascript">//判断浏览器是否支持FileReader接口if (typeof FileReader == 'undefined') {document.getElementById("xmTanContentDiv").InnerHTML = "<p>当前浏览器不支持FileReader接口！</p>";document.getElementById("xmTanFile").setAttribute("disabled", "disabled");}//选择文件function xmTanUploadFile(obj){if (obj.files.length < 1) return;var file = obj.files[0];if (file.size > 1024 * 1024) {alert("文件大于1M， 太大了，小点吧！");obj.value = "";return;}}//读取文件为二进制function readAsBinaryString() {var obj = document.getElementById("xmTanFile");if (obj.files.length < 1) return;var file = obj.files[0];var reader = new FileReader();//将文件以二进制形式读入页面reader.readAsBinaryString(file);reader.onload = function (f) {document.getElementById("xmTanContentDiv").innerHTML = this.result;}}//读取文件为文本function readAsText() {var obj = document.getElementById("xmTanFile");if (obj.files.length < 1) return;var file = obj.files[0];var reader = new FileReader();//将文件以文本形式读入页面reader.readAsText(file);reader.onload = function (f) {document.getElementById("xmTanContentDiv").innerHTML = this.result;}}</script><div style="border: 2px dashed red; padding: 20px 0px;"><label>选择文件：</label><input type="file" id="xmTanFile" accept=".html,.js,.css,.txt,.cs,.xml" οnchange="xmTanUploadFile(this)"/><input type="button" value="读取成二进制数据" οnclick="readAsBinaryString()" /><input type="button" value="读取成文本数据" οnclick="readAsText()" /><input type="button" value="隐藏读取内容" οnclick="document.getElementById('xmTanContentDiv').style.display = 'none';"/><input type="button" value="显示读取内容" οnclick="document.getElementById('xmTanContentDiv').style.display = 'block';"/><div id="xmTanContentDiv"></div></div>

<div style="text-align:center; padding: 5px 20px;width: 70%;"><img id="xmTanShowImg" src=""/><h1><a href="javascript:void()" download="girl.jpg" id="xmTanDownload">点此下载</a></h1></div><script type="text/javascript">//图片转成base64位字符串数据var imgData = "data:image/png;base64,.........";//或直接设置图片链接： var imgData = "images/picture.png";document.getElementById("xmTanShowImg").setAttribute("src", imgData);  //给图片标签设置srcdocument.getElementById("xmTanDownload").setAttribute("href", imgData); //给a标签设置href</script>