<div class="uploadFile"> 
 <span id="doc"><input type="text" disabled="disabled" /></span> 
 <input type="hidden" id="hidFileName" /> 
 <input type="button" id="btnUploadFile" value="上传" /> 
 <input type="button" id="btnDeleteFile" value="删除" /> 
</div> 

<div class="uploadImg"> 
 <img id="imgShow" src="/UploadFiles/2021-04-02/nophoto.gif">

2、引用AjaxUpload.js文件




<script src="/UploadFiles/2021-04-02/AjaxUpload.js">

3、编写JS脚本




window.onload = function() { 
 init(); //初始化 
} 
 
//初始化 
function init() { 
 //初始化文档上传 
 var btnFile = document.getElementById("btnUploadFile"); 
 var doc = document.getElementById("doc"); 
 var hidFileName = document.getElementById("hidFileName"); 
 document.getElementById("btnDeleteFile").onclick = function() { DelFile(doc, hidFileName); }; 
 g_AjxUploadFile(btnFile, doc, hidFileName); 
  
 //初始化图片上传 
 var btnImg = document.getElementById("btnUploadImg"); 
 var img = document.getElementById("imgShow"); 
 var hidImgName = document.getElementById("hidImgName"); 
 document.getElementById("btnDeleteImg").onclick = function() { DelImg(img, hidImgName); }; 
 g_AjxUploadImg(btnImg, img, hidImgName); 
} 
 
 
var g_AjxTempDir = "/file/temp/"; 
//文档上传 
function g_AjxUploadFile(btn, doc, hidPut, action) { 
 var button = btn, interval; 
 new AjaxUpload(button, { 
 action: ((action == null || action == undefined) "您上传的文档格式不对，请重新选择！"); 
    return false; 
   } 
  }, 
  onComplete: function(file, response) { 
   flagValue = response; 
   if (flagValue == "1") { 
    alert("您上传的文档格式不对，请重新选择！"); 
   } 
   else if (flagValue == "2") { 
    alert("您上传的文档大于2M，请重新选择！"); 
   } 
   else if (flagValue == "3") { 
    alert("文档上传失败！"); 
   } 
   else { 
    hidPut.value = response; 
    doc.innerHTML="<a href='" + g_AjxTempDir + response + "' target='_blank'>" + response + "</a>"; 
   } 
  } 
 }); 
} 
//图片上传 
function g_AjxUploadImg(btn, img, hidPut) { 
 var button = btn, interval; 
 new AjaxUpload(button, { 
  action: '/Common/UploadHandler.ashx"您上传的图片格式不对，请重新选择！"); 
    return false; 
   } 
  }, 
  onComplete: function(file, response) { 
   flagValue = response; 
   if (flagValue == "1") { 
    alert("您上传的图片格式不对，请重新选择！"); 
   } 
   else if (flagValue == "2") { 
    alert("您上传的图片大于200K，请重新选择！"); 
   } 
   else if (flagValue == "3") { 
    alert("图片上传失败！"); 
   } 
   else { 
    hidPut.value = response; 
    img.src = g_AjxTempDir + response; 
   } 
  } 
 }); 
} 
 
//删除文档 
function DelFile(doc, hidPut) { 
 hidPut.value = ""; 
 doc.innerHTML = "<input type=\"text\" disabled=\"disabled\" />"; 
} 
 
//删除图片 
function DelImg(img, hidPut) { 
 hidPut.value = ""; 
 img.src = "/images/nophoto.gif"; 
} 


4、创建/Common/UploadHandler.ashx处理程序




<%@ WebHandler Language="C#" Class="UploadHandler" %> 
 
using System; 
using System.Web; 
using System.Text.RegularExpressions; 
using System.IO; 
 
public class UploadHandler : IHttpHandler { 
 private string _filedir = ""; //文件目录 
 /// <summary> 
 /// 处理上传文件(1:文件格式不正确、2:文件大小不正确、3:上传失败、文件名称:上传成功) 
 /// </summary> 
 /// <param name="context"></param> 
 public void ProcessRequest (HttpContext context) { 
  _filedir = context.Server.MapPath(@"/file/temp/"); 
  try 
  { 
   string result = "3"; 
   string fileType = context.Request.QueryString["fileType"]; //获取上传文件类型 
   if (fileType == "file") 
   { 
    result = UploadFile(context); //文档上传 
   } 
   else if (fileType == "img") 
   { 
    result = UploadImg(context); //图片上传 
   } 
   context.Response.Write(result); 
  } 
  catch 
  { 
   context.Response.Write("3");//3文件上传失败 
  } 
 } 
  
 /// <summary> 
 /// 文档上传 
 /// </summary> 
 /// <param name="context"></param> 
 /// <returns></returns> 
 private string UploadFile(HttpContext context) 
 { 
  int cout = context.Request.Files.Count; 
  if (cout > 0) 
  { 
   HttpPostedFile hpf = context.Request.Files[0]; 
   if (hpf != null) 
   { 
    string fileExt = Path.GetExtension(hpf.FileName).ToLower(); 
    //只能上传文件，过滤不可上传的文件类型 
    string fileFilt = ".rar|.zip|.pdf|.pdfx|.txt|.csv|.xls|.xlsx|.doc|.docx......"; 
    if (fileFilt.IndexOf(fileExt) <= -1) 
    { 
     return "1"; 
    } 
     
    //判断文件大小 
    int length = hpf.ContentLength; 
    if (length > 2097152) 
    { 
     return "2"; 
    } 
     
    Random rd = new Random(); 
    DateTime nowTime = DateTime.Now; 
    string newFileName = nowTime.Year.ToString() + nowTime.Month.ToString() + nowTime.Day.ToString() + nowTime.Hour.ToString() + nowTime.Minute.ToString() + nowTime.Second.ToString() + rd.Next(1000, 1000000) + Path.GetExtension(hpf.FileName); 
    if (!Directory.Exists(_filedir)) 
    { 
     Directory.CreateDirectory(_filedir); 
    } 
    string fileName = _filedir + newFileName; 
    hpf.SaveAs(fileName); 
    return newFileName; 
   } 
 
  } 
  return "3"; 
 } 
 
 /// <summary> 
 /// 图片上传 
 /// </summary> 
 /// <param name="context"></param> 
 /// <returns></returns> 
 private string UploadImg(HttpContext context) 
 { 
  int cout = context.Request.Files.Count; 
  if (cout > 0) 
  { 
   HttpPostedFile hpf = context.Request.Files[0]; 
   if (hpf != null) 
   { 
    string fileExt = Path.GetExtension(hpf.FileName).ToLower(); 
    //只能上传文件，过滤不可上传的文件类型 
    string fileFilt = ".gif|.jpg|.php|.jsp|.jpeg|.png|......"; 
    if (fileFilt.IndexOf(fileExt) <= -1) 
    { 
     return "1"; 
    } 
     
    //判断文件大小 
    int length = hpf.ContentLength; 
    if (length > 204800) 
    { 
     return "2"; 
    } 
     
    Random rd = new Random(); 
    DateTime nowTime = DateTime.Now; 
    string newFileName = nowTime.Year.ToString() + nowTime.Month.ToString() + nowTime.Day.ToString() + nowTime.Hour.ToString() + nowTime.Minute.ToString() + nowTime.Second.ToString() + rd.Next(1000, 1000000) + Path.GetExtension(hpf.FileName); 
    if (!Directory.Exists(_filedir)) 
    { 
     Directory.CreateDirectory(_filedir); 
    } 
    string fileName = _filedir + newFileName; 
    hpf.SaveAs(fileName); 
    return newFileName; 
   } 
 
  } 
  return "3"; 
 } 
  
 #region IHttpHandler 成员 
 
 public bool IsReusable 
 { 
  get { throw new NotImplementedException(); } 
 } 
 
 #endregion 
} 


附件1：页面CSS样式




/*上传文件*/ 
.uploadFile{margin-bottom:10px;} 
/*上传图片*/ 
.uploadImg{} 
.uploadImg img{width:102px; height:64px; border:1px solid #CCCCCC; display: block;} 



附件2：AjaxUpload.js文件




/** 
 * AJAX Upload ( http://valums.com/ajax-upload/ ) 
 * Copyright (c) Andris Valums 
 * Licensed under the MIT license ( http://valums.com/mit-license/ ) 
 * Thanks to Gary Haran, David Mark, Corey Burns and others for contributions 
 */ 
(function () { 
 /* global window */ 
 /* jslint browser: true, devel: true, undef: true, nomen: true, bitwise: true, regexp: true, newcap: true, immed: true */ 
 
 /** 
  * Wrapper for FireBug's console.log 
  */ 
 
 function log() { 
  if (typeof(console) != 'undefined' && typeof(console.log) == 'function') { 
   Array.prototype.unshift.call(arguments, '[Ajax Upload]'); 
   console.log(Array.prototype.join.call(arguments, ' ')); 
  } 
 } 
 
 /** 
  * Attaches event to a dom element. 
  * @param {Element} el 
  * @param type event name 
  * @param fn callback This refers to the passed element 
  */ 
 
 function addEvent(el, type, fn) { 
  if (el.addEventListener) { 
   el.addEventListener(type, fn, false); 
  } else if (el.attachEvent) { 
   el.attachEvent('on' + type, function () { 
    fn.call(el); 
   }); 
  } else { 
   throw new Error('not supported or DOM not loaded'); 
  } 
 } 
 
 /** 
  * Attaches resize event to a window, limiting 
  * number of event fired. Fires only when encounteres 
  * delay of 100 after series of events. 
  * 
  * Some browsers fire event multiple times when resizing 
  * http://www.quirksmode.org/dom/events/resize.html 
  * 
  * @param fn callback This refers to the passed element 
  */ 
 
 function addResizeEvent(fn) { 
  var timeout; 
 
  addEvent(window, 'resize', function () { 
   if (timeout) { 
    clearTimeout(timeout); 
   } 
   timeout = setTimeout(fn, 100); 
  }); 
 } 
 
 // Needs more testing, will be rewriten for next version   
 // getOffset function copied from jQuery lib (http://jquery.com/) 
 if (document.documentElement.getBoundingClientRect) { 
  // Get Offset using getBoundingClientRect 
  // http://ejohn.org/blog/getboundingclientrect-is-awesome/ 
  var getOffset = function (el) { 
   var box = el.getBoundingClientRect(); 
   var doc = el.ownerDocument; 
   var body = doc.body; 
   var docElem = doc.documentElement; // for ie 
   var clientTop = docElem.clientTop || body.clientTop || 0; 
   var clientLeft = docElem.clientLeft || body.clientLeft || 0; 
 
   // In Internet Explorer 7 getBoundingClientRect property is treated as physical, 
   // while others are logical. Make all logical, like in IE8. 
   var zoom = 1; 
   if (body.getBoundingClientRect) { 
    var bound = body.getBoundingClientRect(); 
    zoom = (bound.right - bound.left) / body.clientWidth; 
   } 
 
   if (zoom > 1) { 
    clientTop = 0; 
    clientLeft = 0; 
   } 
 
   var top = box.top / zoom + (window.pageYOffset || docElem && docElem.scrollTop / zoom || body.scrollTop / zoom) - clientTop, 
    left = box.left / zoom + (window.pageXOffset || docElem && docElem.scrollLeft / zoom || body.scrollLeft / zoom) - clientLeft; 
 
   return { 
    top: top, 
    left: left 
   }; 
  }; 
 } else { 
  // Get offset adding all offsets 
  var getOffset = function (el) { 
   var top = 0, 
    left = 0; 
   do { 
    top += el.offsetTop || 0; 
    left += el.offsetLeft || 0; 
    el = el.offsetParent; 
   } while (el); 
 
   return { 
    left: left, 
    top: top 
   }; 
  }; 
 } 
 
 /** 
  * Returns left, top, right and bottom properties describing the border-box, 
  * in pixels, with the top-left relative to the body 
  * @param {Element} el 
  * @return {Object} Contains left, top, right,bottom 
  */ 
 
 function getBox(el) { 
  var left, right, top, bottom; 
  var offset = getOffset(el); 
  left = offset.left; 
  top = offset.top; 
 
  right = left + el.offsetWidth; 
  bottom = top + el.offsetHeight; 
 
  return { 
   left: left, 
   right: right, 
   top: top, 
   bottom: bottom 
  }; 
 } 
 
 /** 
  * Helper that takes object literal 
  * and add all properties to element.style 
  * @param {Element} el 
  * @param {Object} styles 
  */ 
 
 function addStyles(el, styles) { 
  for (var name in styles) { 
   if (styles.hasOwnProperty(name)) { 
    el.style[name] = styles[name]; 
   } 
  } 
 } 
 
 /** 
  * Function places an absolutely positioned 
  * element on top of the specified element 
  * copying position and dimentions. 
  * @param {Element} from 
  * @param {Element} to 
  */ 
 
 function copyLayout(from, to) { 
  var box = getBox(from); 
 
  addStyles(to, { 
   position: 'absolute', 
   left: box.left + 'px', 
   top: box.top + 'px', 
   width: from.offsetWidth + 'px', 
   height: from.offsetHeight + 'px' 
  }); 
 } 
 
 /** 
  * Creates and returns element from html chunk 
  * Uses innerHTML to create an element 
  */ 
 var toElement = (function () { 
  var div = document.createElement('div'); 
  return function (html) { 
   div.innerHTML = html; 
   var el = div.firstChild; 
   return div.removeChild(el); 
  }; 
 })(); 
 
 /** 
  * Function generates unique id 
  * @return unique id 
  */ 
 var getUID = (function () { 
  var id = 0; 
  return function () { 
   return 'ValumsAjaxUpload' + id++; 
  }; 
 })(); 
 
 /** 
  * Get file name from path 
  * @param {String} file path to file 
  * @return filename 
  */ 
 
 function fileFromPath(file) { 
  return file.replace(/.*(\/|\\)/, ""); 
 } 
 
 /** 
  * Get file extension lowercase 
  * @param {String} file name 
  * @return file extenstion 
  */ 
 
 function getExt(file) { 
  return (-1 !== file.indexOf('.')) "json" in that case. 
   responseType: false, 
   // Class applied to button when mouse is hovered 
   hoverClass: 'hover', 
   // Class applied to button when AU is disabled 
   disabledClass: 'disabled', 
   // When user selects a file, useful with autoSubmit disabled 
   // You can return false to cancel upload    
   onChange: function (file, extension) {}, 
   // Callback to fire before file is uploaded 
   // You can return false to cancel upload 
   onSubmit: function (file, extension) {}, 
   // Fired when file upload is completed 
   // WARNING! DO NOT USE "FALSE" STRING AS A RESPONSE! 
   onComplete: function (file, response) {} 
  }; 
 
  // Merge the users options with our defaults 
  for (var i in options) { 
   if (options.hasOwnProperty(i)) { 
    this._settings[i] = options[i]; 
   } 
  } 
 
  // button isn't necessary a dom element 
  if (button.jquery) { 
   // jQuery object was passed 
   button = button[0]; 
  } else if (typeof button == "string") { 
   if (/^#.*/.test(button)) { 
    // If jQuery user passes #elementId don't break it     
    button = button.slice(1); 
   } 
 
   button = document.getElementById(button); 
  } 
 
  if (!button || button.nodeType !== 1) { 
   throw new Error("Please make sure that you're passing a valid element"); 
  } 
 
  if (button.nodeName.toUpperCase() == 'A') { 
   // disable link       
   addEvent(button, 'click', function (e) { 
    if (e && e.preventDefault) { 
     e.preventDefault(); 
    } else if (window.event) { 
     window.event.returnValue = false; 
    } 
   }); 
  } 
 
  // DOM element 
  this._button = button; 
  // DOM element     
  this._input = null; 
  // If disabled clicking on button won't do anything 
  this._disabled = false; 
 
  // if the button was disabled before refresh if will remain 
  // disabled in FireFox, let's fix it 
  this.enable(); 
 
  this._rerouteClicks(); 
 }; 
 
 // assigning methods to our class 
 AjaxUpload.prototype = { 
  setData: function (data) { 
   this._settings.data = data; 
  }, 
  disable: function () { 
   addClass(this._button, this._settings.disabledClass); 
   this._disabled = true; 
 
   var nodeName = this._button.nodeName.toUpperCase(); 
   if (nodeName == 'INPUT' || nodeName == 'BUTTON') { 
    this._button.setAttribute('disabled', 'disabled'); 
   } 
 
   // hide input 
   if (this._input) { 
    // We use visibility instead of display to fix problem with Safari 4 
    // The problem is that the value of input doesn't change if it 
    // has display none when user selects a file    
    this._input.parentNode.style.visibility = 'hidden'; 
   } 
  }, 
  enable: function () { 
   removeClass(this._button, this._settings.disabledClass); 
   this._button.removeAttribute('disabled'); 
   this._disabled = false; 
 
  }, 
  /** 
   * Creates invisible file input 
   * that will hover above the button 
   * <div><input type='file' /></div> 
   */ 
  _createInput: function () { 
   var self = this; 
 
   var input = document.createElement("input"); 
   input.setAttribute('type', 'file'); 
   input.setAttribute('name', this._settings.name); 
 
   addStyles(input, { 
    'position': 'absolute', 
    // in Opera only 'browse' button 
    // is clickable and it is located at 
    // the right side of the input 
    'right': 0, 
    'margin': 0, 
    'padding': 0, 
    'fontSize': '480px', 
    'cursor': 'pointer' 
   }); 
 
   var div = document.createElement("div"); 
   addStyles(div, { 
    'display': 'block', 
    'position': 'absolute', 
    'overflow': 'hidden', 
    'margin': 0, 
    'padding': 0, 
    'opacity': 0, 
    // Make sure browse button is in the right side 
    // in Internet Explorer 
    'direction': 'ltr', 
    //Max zIndex supported by Opera 9.0-9.2 
    'zIndex': 2147483583 
   }); 
 
   // Make sure that element opacity exists. 
   // Otherwise use IE filter    
   if (div.style.opacity !== "0") { 
    if (typeof(div.filters) == 'undefined') { 
     throw new Error('Opacity not supported by the browser'); 
    } 
    div.style.filter = "alpha(opacity=0)"; 
   } 
 
   addEvent(input, 'change', function () { 
 
    if (!input || input.value === '') { 
     return; 
    } 
 
    // Get filename from input, required     
    // as some browsers have path instead of it   
    var file = fileFromPath(input.value); 
 
    if (false === self._settings.onChange.call(self, file, getExt(file))) { 
     self._clearInput(); 
     return; 
    } 
 
    // Submit form when value is changed 
    if (self._settings.autoSubmit) { 
     self.submit(); 
    } 
   }); 
 
   addEvent(input, 'mouseover', function () { 
    addClass(self._button, self._settings.hoverClass); 
   }); 
 
   addEvent(input, 'mouseout', function () { 
    removeClass(self._button, self._settings.hoverClass); 
 
    // We use visibility instead of display to fix problem with Safari 4 
    // The problem is that the value of input doesn't change if it 
    // has display none when user selects a file    
    input.parentNode.style.visibility = 'hidden'; 
 
   }); 
 
   div.appendChild(input); 
   document.body.appendChild(div); 
 
   this._input = input; 
  }, 
  _clearInput: function () { 
   if (!this._input) { 
    return; 
   } 
 
   // this._input.value = ''; Doesn't work in IE6         
   removeNode(this._input.parentNode); 
   this._input = null; 
   this._createInput(); 
 
   removeClass(this._button, this._settings.hoverClass); 
  }, 
  /** 
   * Function makes sure that when user clicks upload button, 
   * the this._input is clicked instead 
   */ 
  _rerouteClicks: function () { 
   var self = this; 
 
   // IE will later display 'access denied' error 
   // if you use using self._input.click() 
   // other browsers just ignore click() 
 
   addEvent(self._button, 'mouseover', function () { 
    if (self._disabled) { 
     return; 
    } 
 
    if (!self._input) { 
     self._createInput(); 
    } 
 
    var div = self._input.parentNode; 
    copyLayout(self._button, div); 
    div.style.visibility = 'visible'; 
 
   }); 
 
 
   // commented because we now hide input on mouseleave 
   /** 
    * When the window is resized the elements 
    * can be misaligned if button position depends 
    * on window size 
    */ 
   //addResizeEvent(function(){ 
   // if (self._input){ 
   //  copyLayout(self._button, self._input.parentNode); 
   // } 
   //});    
 
  }, 
  /** 
   * Creates iframe with unique name 
   * @return {Element} iframe 
   */ 
  _createIframe: function () { 
   // We can't use getTime, because it sometimes return 
   // same value in safari :( 
   var id = getUID(); 
 
   // We can't use following code as the name attribute 
   // won't be properly registered in IE6, and new window 
   // on form submit will open 
   // var iframe = document.createElement('iframe'); 
   // iframe.setAttribute('name', id);       
 
   var iframe = toElement('<iframe src="/UploadFiles/2021-04-02/javascript:false;">

更多精彩内容请参考专题《ajax上传技术汇总》，《javascript文件上传操作汇总》和《jQuery上传操作汇总》进行学习。
以上就是ajaxupload实现文件上传操作的详细代码，希望对大家的学习有所帮助。

                                
                                

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