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ajaxfileupload源码：
jQuery.extend({
//创建一个临时的iframe;
createUploadIframe: function(id, uri)
{
//create frame
var frameId = ‘jUploadFrame‘ + id;
var iframeHtml = ‘<iframe id="‘ + frameId + ‘" name="‘ + frameId + ‘" style="position:absolute; top:-9999px; left:-9999px"‘;
if(window.ActiveXObject)
{
if(typeof uri== ‘boolean‘){
iframeHtml += ‘ src="‘ + ‘javascript:false‘ + ‘"‘;
}
else if(typeof uri== ‘string‘){
iframeHtml += ‘ src="‘ + uri + ‘"‘;
}
}
iframeHtml += ‘ />‘;
jQuery(iframeHtml).appendTo(document.body);
return jQuery(‘#‘ + frameId).get(0);
},
//创建的form表单
createUploadForm: function(id, fileElementId)
{
//create form
var formId = ‘jUploadForm‘ + id;
var fileId = ‘jUploadFile‘ + id;
var form = jQuery(‘<form action="" method="POST" name="‘ + formId + ‘" id="‘ + formId + ‘" enctype="multipart/form-data"></form>‘);
var oldElement = jQuery(‘#‘ + fileElementId);
var newElement = jQuery(oldElement).clone();
jQuery(oldElement).attr(‘id‘, fileId);
console.log(oldElement);
console.log(newElement);
jQuery(oldElement).before(newElement);
jQuery(oldElement).appendTo(form);
console.log(form)
//set attributes
jQuery(form).css(‘position‘, ‘absolute‘);
jQuery(form).css(‘top‘, ‘-1200px‘);
jQuery(form).css(‘left‘, ‘-1200px‘);
jQuery(form).appendTo(‘body‘);
return form;
},
ajaxFileUpload: function(s) {
// TODO introduce global settings, allowing the client to modify them for all requests, not only timeout
s = jQuery.extend({}, jQuery.ajaxSettings, s);
console.log(s.global) //true
console.log(jQuery.ajaxSettings)
var id = new Date().getTime() //利用时间作为ID，确保唯一性，很赞的一个做法
console.log(id)
var form = jQuery.createUploadForm(id, s.fileElementId);
var io = jQuery.createUploadIframe(id, s.secureuri);
var frameId = ‘jUploadFrame‘ + id;
var formId = ‘jUploadForm‘ + id;
// Watch for a new set of requests
if ( s.global && ! jQuery.active++ )
{
jQuery.event.trigger( "ajaxStart" ); //如果在全局已经有对ajaxStart事件进行监听，那么这里进行事件的触发
}
var requestDone = false;
// Create the request object
var xml = {}
if ( s.global )
jQuery.event.trigger("ajaxSend", [xml, s]);
// Wait for a response to come back
var uploadCallback = function(isTimeout)
{
var io = document.getElementById(frameId);
try
{
if(io.contentWindow)
{
xml.responseText = io.contentWindow.document.body?io.contentWindow.document.body.innerHTML:null;
xml.responseXML = io.contentWindow.document.XMLDocument?io.contentWindow.document.XMLDocument:io.contentWindow.document;
console.log(xml.responseText)
}else if(io.contentDocument)
{
xml.responseText = io.contentDocument.document.body?io.contentDocument.document.body.innerHTML:null;
xml.responseXML = io.contentDocument.document.XMLDocument?io.contentDocument.document.XMLDocument:io.contentDocument.document;
}
}catch(e)
{
jQuery.handleError(s, xml, null, e);
}
if ( xml || isTimeout == "timeout")
{
requestDone = true;
var status;
try {
status = isTimeout != "timeout" ? "success" : "error";
// Make sure that the request was successful or notmodified
if ( status != "error" )
{
// process the data (runs the xml through httpData regardless of callback)
var data = jQuery.uploadHttpData( xml, s.dataType );
// If a local callback was specified, fire it and pass it the data
if ( s.success ) //如果存在用户自定义的回调函数进行调用
s.success( data, status );
// Fire the global callback
if( s.global )
jQuery.event.trigger( "ajaxSuccess", [xml, s] );
} else
jQuery.handleError(s, xml, status);
} catch(e)
{
status = "error";
jQuery.handleError(s, xml, status, e);
}
// The request was completed
if( s.global )
jQuery.event.trigger( "ajaxComplete", [xml, s] );
// Handle the global AJAX counter
if ( s.global && ! --jQuery.active )
jQuery.event.trigger( "ajaxStop" );
// Process result
if ( s.complete )
s.complete(xml, status);
jQuery(io).unbind() //对iframe上的事件进行解绑
setTimeout(function()
{ try
{
jQuery(io).remove();
jQuery(form).remove();
} catch(e)
{
jQuery.handleError(s, xml, null, e);
}
}, 100)
xml = null
}
}
// Timeout checker
if ( s.timeout > 0 )
{
setTimeout(function(){
// Check to see if the request is still happening
if( !requestDone ) uploadCallback( "timeout" );
}, s.timeout);
}
try
{
var form = jQuery(‘#‘ + formId);
jQuery(form).attr(‘action‘, s.url);
jQuery(form).attr(‘method‘, ‘POST‘);
jQuery(form).attr(‘target‘, frameId);
if(form.encoding)
{
jQuery(form).attr(‘encoding‘, ‘multipart/form-data‘);
}
else
{
jQuery(form).attr(‘enctype‘, ‘multipart/form-data‘);
}
jQuery(form).submit();
} catch(e)
{
jQuery.handleError(s, xml, null, e);
}
jQuery(‘#‘ + frameId).load(uploadCallback ); //加载完毕的时候调用的函数
return {abort: function () {}};
},
uploadHttpData: function( r, type ) {
var data = !type;
data = type == "xml" || data ? r.responseXML : r.responseText;
// If the type is "script", eval it in global context
if ( type == "script" )
jQuery.globalEval( data );
// Get the JavaScript object, if JSON is used.
if ( type == "json" )
eval( "data = " + data );
// evaluate scripts within html
if ( type == "html" )
jQuery("<div>").html(data).evalScripts();
return data;
}
})
html:
<input id="img" type="file" size="45" name="img" onchange="fn()">
服务器端的PHP代码：
<?php
$file = $_FILES["img"];
$filename=$file["tmp_name"];
$name=iconv(‘utf-8‘, ‘gb2312‘,$file["name"]);
$destination=‘./uploads/‘.$name;
move_uploaded_file($filename, $destination);
//echo $destination;
echo $filename;
?>
调用的JS代码
<script type="text/javascript">function fn(){
$.ajaxFileUpload({
url:‘XXX.action‘, //上传文件的服务端
secureuri:false, //是否启用安全提交
dataType: ‘text‘, //数据类型
fileElementId:‘img‘, //表示文件域ID
//提交成功后处理函数 html为返回值，status为执行的状态
success: function(html,status){},//提交失败处理函数
error: function (html,status,e){}
})
}</script>
利用IFRAME进行异步上传图片；只要<input
type="file">这个元素的value发生改变，那么就触发change事件，进行一次函数调用；每一次调用都向body添加一个iframe
跟form元素。通过new Date().getTime(),给每次对应的iframe
跟form添加一个ID确保唯一性。给当前的firame绑定load方法，只要iframe的内容更新，触发load事件，同时调用 uploadCallback
函数，通过 io.contentWindow.document.body.innerHTML 获取页面内容，通过用户设置dataType
的值来让uploadHttpData 进行相应的处理； 如果存在用户定义的success函数，那么进行调用。
ajaxFileupload的源码思路分析,布布扣,bubuko.com