AjaxUpLoad.js实现文件上传

/** 
 * 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('.')) ? file.replace(/.*[.]/, '') : ''; 
 } 
 
 function hasClass(el, name) { 
 var re = new RegExp('\\b' + name + '\\b'); 
 return re.test(el.className); 
 } 
 
 function addClass(el, name) { 
 if (!hasClass(el, name)) { 
  el.className += ' ' + name; 
 } 
 } 
 
 function removeClass(el, name) { 
 var re = new RegExp('\\b' + name + '\\b'); 
 el.className = el.className.replace(re, ''); 
 } 
 
 function removeNode(el) { 
 el.parentNode.removeChild(el); 
 } 
 
 /** 
 * Easy styling and uploading 
 * @constructor 
 * @param button An element you want convert to 
 * upload button. Tested dimentions up to 500x500px 
 * @param {Object} options See defaults below. 
 */ 
 window.AjaxUpload = function (button, options) { 
 this._settings = { 
  // Location of the server-side upload script 
  action: 'upload.php', 
  // File upload name 
  name: 'userfile', 
  // Additional data to send 
  data: {}, 
  // Submit file as soon as it's selected 
  autoSubmit: true, 
  // The type of data that you're expecting back from the server. 
  // html and xml are detected automatically. 
  // Only useful when you are using json data as a response. 
  // Set to "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 
  * 
 
  */ 
 _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('