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关于ajax上传文件的流程

关键点:

1.制作一个表单..然后把上传字段附加到该表单中

2.制作一个框架..把表单的_target的属性指向该框架.

3.提交表单..

 

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="http://www.mamicode.com/ + javascript:false + ";                }                else if(typeof uri== string){                    iframeHtml +=  src="http://www.mamicode.com/ + uri + ";                }                }            iframeHtml +=  />;            jQuery(iframeHtml).appendTo(document.body);            return jQuery(# + frameId).get(0);                },    createUploadForm: function(id, fileElementId, data)    {        //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="http://www.mamicode.com/ + data[i] + " />).appendTo(form);            }                    }                var oldElement = jQuery(# + fileElementId);        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));        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;                     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 =http://www.mamicode.com/ 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 () {}};        },    uploadHttpData: function( r, type ) {        var data = http://www.mamicode.com/!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 = http://www.mamicode.com/" + data );        // evaluate scripts within html        if ( type == "html" )            jQuery("<div>").html(data).evalScripts();        return data;    }})

 

关于ajax上传文件的流程