采用html5使得选择图片改变时，预览框中图片随之改变。input文件选择框美化。原生js完成文件异步提交
效果图：
代码如下，可直接复制并保存为html文件打开查看效果
<html> <head> <title>Title</title> <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css"> <script src="http://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script> <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/js/bootstrap.min.js"></script> <script> // html5实现图片预览功能 $(function(){ $("#file").change(function(e){ var file = e.target.files[0]||e.dataTransfer.files[0]; $('#photoCover').val(document.getElementById("file").files[0].name); if(file){ var reader = new FileReader(); reader.onload=function(){ $("img").attr("src", this.result); } reader.readAsDataURL(file); } }); }) function saveUser(){ var id = $("#id").val().trim(); var uname = $("#uname").val().trim(); var pwd = $("#pwd").val().trim(); var file = document.getElementById("file").files[0]; // 原生ajax实现文件上传 var form = new FormData(); form.append("uname", uname); // 可以增加表单数据 form.append("id", id); form.append("pwd", pwd); if(file){ form.append("file", file); } var xhr = null; //得到xhr对象 if(XMLHttpRequest){ xhr = new XMLHttpRequest(); }else{ xhr = new ActiveXObject("Microsoft.XMLHTTP"); } xhr.open("post", "${ctx}/user/save", true);//设置提交方式，url，异步提交 xhr.onload = function () { var data = xhr.responseText; //得到返回值 // alert(data); var errorMsg = JSON.parse(data); alert(errorMsg.msg); if(errorMsg.code == "0"){ alert("success"); //成功 } } xhr.send(form); } </script> </head> <body style="overflow:scroll;overflow-y:hidden;overflow-x:hidden"> <div style="height: 20px"></div> <div class="container"> <div class="row"> <div class="col-md-6 col-md-offset-3"> <form class="form-horizontal" enctype="multipart/form-data" role="form"> <input type="hidden" value="${user.id}" id="id"/> <div class="control-group"> <label for="uname" class="col-md-3 control-label span3">姓 名:</label> <div class="col-md-9"> <input type="text" class="form-control span3" value="" id="uname" placeholder="请输入姓名"> </div> </div> <div class="control-group"> <label for="pwd" class="col-md-3 control-label span3">密码:</label> <div class="col-md-9"> <input type="password" class="form-control span3" value="" id="pwd" placeholder="请输入密码"> </div> </div> <div class="control-group"> <label class="col-md-3 control-label span3"></label> <div class="col-md-9"> <img src="" width="100px" height="100px"> </div> </div> <div class="control-group"> <label for="requirement" class="col-md-3 control-label span3">图片上传</label> <div class="col-md-9"> <div class="input-group"> <input id="photoCover" class="form-control" readonly type="text"> <label class="input-group-btn"> <input id="file" type="file" style="left:-9999px;position:absolute;"> <span class="btn btn-default">Browse</span> </label> </div> </div> </div> <div class="control-group"> <label class="col-md-2 control-label span2"></label> <div class="col-md-10"> <button type="button" class="btn btn-small btn-primary" onclick="saveUser()">提交</button> <a type="button" class="btn btn-small btn-danger">取消</a> </div> </div> </form> </div> </div> </div> </body> </html>