以下是本人实现ajax上传图片时参考的文章，希望能对大家有帮助。
在PHP网站开发中，文件上传功能时常用到，之前我已介绍过如何利用PHP实现文件上传功能。随着WEB技术的发展，用户体验成为衡量网站成功与否的关键，今天和大家分享如何在PHP中利用Jquery实现Ajax方式文件上传功能的例子，其中使用到了Jquery插件Ajaxupload，其可以实现单个文件和多文件上传功能。
AjaxUpload
Jquery插件AjaxUpload实现文件上传功能时无需创建form表单，即可实现Ajax方式的文件上传，当然根据需要也可以创建form表单。
准备工作
1、下载Jquery开发包和文件上传插件AjaxUpload。
ajaxupload.3.5.js 文件源码：
/**
* Ajax upload
* Project page - http://valums.com/ajax-upload/
* Copyright (c) 2008 Andris Valums, http://valums.com
* Licensed under the MIT license (http://valums.com/mit-license/)
* Version 3.5 (23.06.2009)
*/
/**
* Changes from the previous version:
* 1. Added better JSON handling that allows to use 'application/javascript' as a response
* 2. Added demo for usage with jQuery UI dialog
* 3. Fixed IE "mixed content" issue when used with secure connections
*
* For the full changelog please visit:
* http://valums.com/ajax-upload-changelog/
*/
(function(){
var d = document, w = window;
/**
* Get element by id
*/
function get(element){
if (typeof element == "string")
element = d.getElementById(element);
return element;
}
/**
* Attaches event to a dom element
*/
function addEvent(el, type, fn){
if (w.addEventListener){
el.addEventListener(type, fn, false);
} else if (w.attachEvent){
var f = function(){
fn.call(el, w.event);
};
el.attachEvent('on' + type, f)
}
}
/**
* Creates and returns element from html chunk
*/
var toElement = function(){
var div = d.createElement('div');
return function(html){
div.innerHTML = html;
var el = div.childNodes[0];
div.removeChild(el);
return el;
}
}();
function hasClass(ele,cls){
return ele.className.match(new RegExp('(\\s|^)'+cls+'(\\s|$)'));
}
function addClass(ele,cls) {
if (!hasClass(ele,cls)) ele.className += " "+cls;
}
function removeClass(ele,cls) {
var reg = new RegExp('(\\s|^)'+cls+'(\\s|$)');
ele.className=ele.className.replace(reg,' ');
}
// 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(),
doc = el.ownerDocument,
body = doc.body,
docElem = doc.documentElement,
// for ie
clientTop = docElem.clientTop || body.clientTop || 0,
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.
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){
if (w.jQuery){
return jQuery(el).offset();
}
var top = 0, left = 0;
do {
top += el.offsetTop || 0;
left += el.offsetLeft || 0;
}
while (el = el.offsetParent);
return {
left: left,
top: top
};
}
}
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
};
}
/**
* Crossbrowser mouse coordinates
*/
function getMouseCoords(e){
// pageX/Y is not supported in IE
// http://www.quirksmode.org/dom/w3c_cssom.html
if (!e.pageX && e.clientX){
// In Internet Explorer 7 some properties (mouse coordinates) are treated as physical,
// while others are logical (offset).
var zoom = 1;
var body = document.body;
if (body.getBoundingClientRect) {
var bound = body.getBoundingClientRect();
zoom = (bound.right - bound.left)/body.clientWidth;
}
return {
x: e.clientX / zoom + d.body.scrollLeft + d.documentElement.scrollLeft,
y: e.clientY / zoom + d.body.scrollTop + d.documentElement.scrollTop
};
}
return {
x: e.pageX,
y: e.pageY
};
}
/**
* Function generates unique id
*/
var getUID = function(){
var id = 0;
return function(){
return 'ValumsAjaxUpload' + id++;
}
}();
function fileFromPath(file){
return file.replace(/.*(\/|\\)/, "");
}
function getExt(file){
return (/[.]/.exec(file)) ? /[^.]+$/.exec(file.toLowerCase()) : '';
}
// Please use AjaxUpload , Ajax_upload will be removed in the next version
Ajax_upload = AjaxUpload = function(button, options){
if (button.jquery){
// jquery object was passed
button = button[0];
} else if (typeof button == "string" && /^#.*/.test(button)){
button = button.slice(1);
}
button = get(button);
this._input = null;
this._button = button;
this._disabled = false;
this._submitting = false;
// Variable changes to true if the button was clicked
// 3 seconds ago (requred to fix Safari on Mac error)
this._justClicked = false;
this._parentDialog = d.body;
if (window.jQuery && jQuery.ui && jQuery.ui.dialog){
var parentDialog = jQuery(this._button).parents('.ui-dialog');
if (parentDialog.length){
this._parentDialog = parentDialog[0];
}
}
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,
// When user selects a file, useful with autoSubmit disabled
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) {
this._settings[i] = options[i];
}
this._createInput();
this._rerouteClicks();
}
// assigning methods to our class
AjaxUpload.prototype = {
setData : function(data){
this._settings.data = data;
},
disable : function(){
this._disabled = true;
},
enable : function(){
this._disabled = false;
},
// removes ajaxupload
destroy : function(){
if(this._input){
if(this._input.parentNode){
this._input.parentNode.removeChild(this._input);
}
this._input = null;
}
},
/**
* Creates invisible file input above the button
*/
_createInput : function(){
var self = this;
var input = d.createElement("input");
input.setAttribute('type', 'file');
input.setAttribute('name', this._settings.name);
var styles = {
'position' : 'absolute'
,'margin': '-5px 0 0 -175px'
,'padding': 0
,'width': '220px'
,'height': '30px'
,'fontSize': '14px'
,'opacity': 0
,'cursor': 'pointer'
,'display' : 'none'
,'zIndex' : 2147483583 //Max zIndex supported by Opera 9.0-9.2x
// Strange, I expected 2147483647
};
for (var i in styles){
input.style[i] = styles[i];
}
// Make sure that element opacity exists
// (IE uses filter instead)
if ( ! (input.style.opacity === "0")){
input.style.filter = "alpha(opacity=0)";
}
this._parentDialog.appendChild(input);
addEvent(input, 'change', function(){
// get filename from input
var file = fileFromPath(this.value);
if(self._settings.onChange.call(self, file, getExt(file)) == false ){
return;
}
// Submit form when value is changed
if (self._settings.autoSubmit){
self.submit();
}
});
// Fixing problem with Safari
// The problem is that if you leave input before the file select dialog opens
// it does not upload the file.
// As dialog opens slowly (it is a sheet dialog which takes some time to open)
// there is some time while you can leave the button.
// So we should not change display to none immediately
addEvent(input, 'click', function(){
self.justClicked = true;
setTimeout(function(){
// we will wait 3 seconds for dialog to open
self.justClicked = false;
}, 3000);
});
this._input = input;
},
_rerouteClicks : function (){
var self = this;
// IE displays 'access denied' error when using this method
// other browsers just ignore click()
// addEvent(this._button, 'click', function(e){
// self._input.click();
// });
var box, dialogOffset = {top:0, left:0}, over = false;
addEvent(self._button, 'mouseover', function(e){
if (!self._input || over) return;
over = true;
box = getBox(self._button);
if (self._parentDialog != d.body){
dialogOffset = getOffset(self._parentDialog);
}
});
// we can't use mouseout on the button,
// because invisible input is over it
addEvent(document, 'mousemove', function(e){
var input = self._input;
if (!input || !over) return;
if (self._disabled){
removeClass(self._button, 'hover');
input.style.display = 'none';
return;
}
var c = getMouseCoords(e);
if ((c.x >= box.left) && (c.x <= box.right) &&
(c.y >= box.top) && (c.y <= box.bottom)){
input.style.top = c.y - dialogOffset.top + 'px';
input.style.left = c.x - dialogOffset.left + 'px';
input.style.display = 'block';
addClass(self._button, 'hover');
} else {
// mouse left the button
over = false;
if (!self.justClicked){
input.style.display = 'none';
}
removeClass(self._button, 'hover');
}
});
},
/**
* Creates iframe with unique name
*/
_createIframe : function(){
// unique name
// We cannot use getTime, because it sometimes return
// same value in safari :(
var id = getUID();
// Remove ie6 "This page contains both secure and nonsecure items" prompt
// http://tinyurl.com/77w9wh
var iframe = toElement('<iframe src="javascript:false;" name="' + id + '" />');
iframe.id = id;
iframe.style.display = 'none';
d.body.appendChild(iframe);
return iframe;
},
/**
* Upload file without refreshing the page
*/
submit : function(){
var self = this, settings = this._settings;
if (this._input.value === ''){
// there is no file
return;
}
// get filename from input
var file = fileFromPath(this._input.value);
// execute user event
if (! (settings.onSubmit.call(this, file, getExt(file)) == false)) {
// Create new iframe for this submission
var iframe = this._createIframe();
// Do not submit if user function returns false
var form = this._createForm(iframe);
form.appendChild(this._input);
form.submit();
d.body.removeChild(form);
form = null;
this._input = null;
// create new input
this._createInput();
var toDeleteFlag = false;
addEvent(iframe, 'load', function(e){
if (// For Safari
iframe.src == "javascript:'%3Chtml%3E%3C/html%3E';" ||
// For FF, IE
iframe.src == "javascript:'<html></html>';"){
// First time around, do not delete.
if( toDeleteFlag ){
// Fix busy state in FF3
setTimeout( function() {
d.body.removeChild(iframe);
}, 0);
}
return;
}
var doc = iframe.contentDocument ? iframe.contentDocument : frames[iframe.id].document;
// fixing Opera 9.26
if (doc.readyState && doc.readyState != 'complete'){
// Opera fires load event multiple times
// Even when the DOM is not ready yet
// this fix should not affect other browsers
return;
}
// fixing Opera 9.64
if (doc.body && doc.body.innerHTML == "false"){
// In Opera 9.64 event was fired second time
// when body.innerHTML changed from false
// to server response approx. after 1 sec
return;
}
var response;
if (doc.XMLDocument){
// response is a xml document IE property
response = doc.XMLDocument;
} else if (doc.body){
// response is html document or plain text
response = doc.body.innerHTML;
if (settings.responseType && settings.responseType.toLowerCase() == 'json'){
// If the document was sent as 'application/javascript' or
// 'text/javascript', then the browser wraps the text in a <pre>
// tag and performs html encoding on the contents. In this case,
// we need to pull the original text content from the text node's
// nodeValue property to retrieve the unmangled content.
// Note that IE6 only understands text/html
if (doc.body.firstChild && doc.body.firstChild.nodeName.toUpperCase() == 'PRE'){
response = doc.body.firstChild.firstChild.nodeValue;
}
if (response) {
response = window["eval"]("(" + response + ")");
} else {
response = {};
}
}
} else {
// response is a xml document
var response = doc;
}
settings.onComplete.call(self, file, response);
// Reload blank page, so that reloading main page
// does not re-submit the post. Also, remember to
// delete the frame
toDeleteFlag = true;
// Fix IE mixed content issue
iframe.src = "javascript:'<html></html>';";
});
} else {
// clear input to allow user to select same file
// Doesn't work in IE6
// this._input.value = '';
d.body.removeChild(this._input);
this._input = null;
// create new input
this._createInput();
}
},
/**
* Creates form, that will be submitted to iframe
*/
_createForm : function(iframe){
var settings = this._settings;
// method, enctype must be specified here
// because changing this attr on the fly is not allowed in IE 6/7
var form = toElement('<form method="post" enctype="multipart/form-data"></form>');
form.style.display = 'none';
form.action = settings.action;
form.target = iframe.name;
d.body.appendChild(form);
// Create hidden input element for each data key
for (var prop in settings.data){
var el = d.createElement("input");
el.type = 'hidden';
el.name = prop;
el.value = settings.data[prop];
form.appendChild(el);
}
return form;
}
};
})();
2、创建uploadfile.html，并引入Jquery开发包和AjaxUpload插件
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1 |
<script src="js/jquery-1.3.js"></script> |
3、根据Jquery插件AjaxUpload的需要，创建一个触发Ajax文件上传功能的DIV
|
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<ul> |
注释：由下面的代码我们可以看到Jquery插件AjaxUpload是根据upload_button这个DIV触发文件上传功能。
前台JS代码
在代码中我设置了开关，根据需要可以匹配上传文件类型，同时也可以设置是以Ajax方式实现单个文件上传还是多个文件上传。
|
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$(document).ready(function(){ |
注释：
第1行：$(document).ready()函数，Jquery中的函数，类似于window.load，使用这个函数可在DOM载入就绪能够读取并操纵时立即调用绑定的函数。
第3行：fileType和fileNum参数代表上传文件的类型和数量，默认值为可上传所有类型文件，同一时间只能上传一个文件，如想上传图片文件或同时上传多个文件，可将这两个变量值变为pic和more。
第6~8行：POST到服务器的数据，你可以设置静态值也可以通过Jquery的DOM操作函数获得一些动态值，比如form表单中INPUT的值等。
第9行：等同于前端
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<input type="file" name="userfile"> |
服务器端$_FILES['userfile']
第10~36行：文件上传前触发的功能。
第11~21行：图片文件类型的过滤功能，Jquery setData函数用来设置POST至服务器端的值。
第25~26行：设置同时只上传一个文件还是多个文件，如果只上传一个文件，则将触发按钮禁掉。如果要多传输几个文件，请在服务器端PHP文件上传程序中设置MAXSIZE的值，当然上传文件的大小限制同时和PHP.INI文件中的设置也有关。
第28~35行：在文件上传过程中每隔200毫秒动态更新一次按钮的文字，已实现动态提示的效果。window.setInterval函数用来每隔指定的时间就执行一次内置的函数，交互时间单位为豪秒。
第37~49行：文件上传功能完成后触发的功能，根据返回值如果服务器端报错，则前端通过ALERT方式提示出错信息。
服务器端PHP文件上传代码
大体上是根据之前介绍的PHP文件上传功能代码实例教程改编，涉及到的文件上传大小的设置，出错信息等说明都已在此文中详细说明。
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$upload_dir = '../file/'; |
总结
基本上前端Ajax文件上传触发功能和服务器端PHP文件上传功能的原型就介绍完毕了，你可以根据自身需要对前后端代码进行补充，也可以将一些 功能独立出来，比如文件类型、单个文件或者多文件上传功能。总的来说Jquery插件AjaxUpload实现文件上传功能的应用还是比较容易的。
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原始连接（http://www.leapsoul.cn/?p=304）