js代码functionsubmitform(){$("#form_upload").ajaxSubmit({success:showResponse});}functionshowResponse(responseText){if(responseText!=null){alert('上传成功！');}else{alert('操作失败！');}}$(function(){$("#upImg").on("change",function(){varfile=this.files[0];if(this.files&&file){varreader=newFileReader();reader.onload=function(e){$('#result').attr('src',e.target.result);}reader.readAsDataURL(file);}});})

前台代码<table><tr><td>生产(经营)许可证证件照片</td><td><formid="form_upload"action="Upload"target="iframeInfo"method="post"enctype="multipart/form-data"><inputname="upImg"id="upImg"type="file"/><inputtype="submit"value="上传"/></form></td></tr><tr><td><imgid="result"src=""alt=""></td><td><iframename="iframeInfo"id="iframeInfo"></iframe></td></tr></table>（这里添加iframe，因为后台返回时会跳转，把form放入iframe里提交就不会跳转页面）

后台代码[HttpPost]publicActionResultUpload(HttpPostedFileBaseupImg){if(upImg==null){returnContent("文件上传错误，请重新选择文件！");}stringfileName=System.IO.Path.GetFileName(upImg.FileName);stringfilePhysicalPath=Server.MapPath("~/credp_w_picpaths/"+fileName);try{upImg.SaveAs(filePhysicalPath);Session["ImgPath"]=filePhysicalPath;returnContent("上传成功");}catch{returnContent("上传异常！");}}