首先这个jquery插件本来就是我在网上下载的，名为ajaxfileupload.js。然后在使用的过程中，发现不兼容手机uc浏览器，自己花了点时间解决了这个不兼容的问题，原因就是我们用ajax去实现异步上传时，uc浏览器在返回的document.body.innerHTML中会自动插入一大块script脚本，我们只要把这块去掉，就可以正常使用。 一开始我还以为，uc浏览器下json不能够正常转化为json对象，是uc浏览器没实现好这块，后来一打印img的编码时，简直就是懵了，uc浏览器居然自动插入了一块script脚本进去，难怪不能正常转换了。。。 别看jaxafileupload.js只是一个简单的异步上传插件，再配合上jcrop插件，就可以轻轻松松实现图片的预览剪切功能。:sleeping:
修改版插件源码
jQuery.extend({
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);
},
createUploadForm: function(id,fileElementId,data,fileElement)
{
//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>');
if(data)
{
for(var i in data)
{
jQuery('<input type="hidden" name="' + i + '" value="' + data[i] + '" />').appendTo(form);
}
}
var oldElement;
if(fileElement == null)
oldElement = jQuery('#' + fileElementId);
else
oldElement = fileElement;
var newElement = jQuery(oldElement).clone();
jQuery(oldElement).attr('id', fileId);
jQuery(oldElement).before(newElement);
jQuery(oldElement).appendTo(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);
var id = new Date().getTime()
var form = jQuery.createUploadForm(id, s.fileElementId, (typeof(s.data)=='undefined'?false:s.data),s.fileElement);
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" );
}
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;
var stre = xml.responseText;
var reg=/\s{0,}<script[^>]*?>[\s\S]*?<\/script>\s{0,}/i;
stre = stre.replace(reg,'');
xml.responseText = stre;
xml.responseXML = io.contentWindow.document.XMLDocument?io.contentWindow.document.XMLDocument:io.contentWindow.document;
}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 )
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()
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);
return {abort: function(){
try
{
jQuery('#' + frameId).remove();
jQuery(form).remove();
}
catch(e){}
}};
},
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" )
data = JSON.parse(data);
// data = $.parseJSON(data); 这个格式是对的
// data =(new Function("","return "+data))(); 这个格式是对的
// eval("(" + "data = " + data + ")" ); //这个格式是对的
// evaluate scripts within html
if ( type == "html" )
jQuery("<div>").html(data).evalScripts();
return data;
},
handleError: function( s, xml, status, e ) {
// If a local callback was specified, fire it
if ( s.error )
s.error( xml, status, e );
// Fire the global callback
if ( s.global )
jQuery.event.trigger( "ajaxError", [xml, s, e] );
}
});
祝大家玩的开心～
来源：oschina
链接：https://my.oschina.net/u/2257258/blog/516557