原理：下载文件时设置一个cookie，客户端利用js间隔性检测cookie，如果检测到则服务端对下载的文件处理完毕，然后通知客户端
下载地址：https://github.com/johnculviner/jquery.fileDownload/blob/master/src/Scripts/jquery.fileDownload.js
/* * jQuery File Download Plugin v1.3.3 * * http://www.johnculviner.com * * Copyright (c) 2012 - John Culviner * * Licensed under the MIT license: * http://www.opensource.org/licenses/mit-license.php */ var $ = jQuery.noConflict(); $.extend({ // //$.fileDownload('/path/to/url/', options) // see directly below for possible 'options' fileDownload: function (fileUrl, options) { var defaultFailCallback = function (responseHtml, url) { alert("A file download error has occurred, please try again."); }; //provide some reasonable defaults to any unspecified options below var settings = $.extend({ // //Requires jQuery UI: provide a message to display to the user when the file download is being prepared before the browser's dialog appears // preparingMessageHtml: null, // //Requires jQuery UI: provide a message to display to the user when a file download fails // failMessageHtml: null, // //the stock android browser straight up doesn't support file downloads initiated by a non GET: http://code.google.com/p/android/issues/detail?id=1780 //specify a message here to display if a user tries with an android browser //if jQuery UI is installed this will be a dialog, otherwise it will be an alert // androidPostUnsupportedMessageHtml: "Unfortunately your Android browser doesn't support this type of file download. Please try again with a different browser.", // //Requires jQuery UI: options to pass into jQuery UI Dialog // dialogOptions: { modal: true }, // //a function to call after a file download dialog/ribbon has appeared //Args: // url - the original url attempted // successCallback: function (url) { }, // //a function to call after a file download dialog/ribbon has appeared //Args: // responseHtml - the html that came back in response to the file download. this won't necessarily come back depending on the browser. // in less than IE9 a cross domain error occurs because 500+ errors cause a cross domain issue due to IE subbing out the // server's error message with a "helpful" IE built in message // url - the original url attempted // failCallback: defaultFailCallback, // // the HTTP method to use. Defaults to "GET". // httpMethod: "GET", // // if specified will perform a "httpMethod" request to the specified 'fileUrl' using the specified data. // data must be an object (which will be $.param serialized) or already a key=value param string // data: null, // //a period in milliseconds to poll to determine if a successful file download has occured or not // checkInterval: 100, // //the cookie name to indicate if a file download has occured // cookieName: "fileDownload", // //the cookie value for the above name to indicate that a file download has occured // cookieValue: "true", // //the cookie path for above name value pair // cookiePath: "/", // //the title for the popup second window as a download is processing in the case of a mobile browser // popupWindowTitle: "Initiating file download...", // //Functionality to encode HTML entities for a POST, need this if data is an object with properties whose values contains strings with quotation marks. //HTML entity encoding is done by replacing all &,<,>,',",\r,\n characters. //Note that some browsers will POST the string htmlentity-encoded whilst others will decode it before POSTing. //It is recommended that on the server, htmlentity decoding is done irrespective. // encodeHTMLEntities: true }, options); //Setup mobile browser detection: Partial credit: http://detectmobilebrowser.com/ var userAgent = (navigator.userAgent || navigator.vendor || window.opera).toLowerCase(); var isIos = false; //has full support of features in iOS 4.0+, uses a new window to accomplish this. var isAndroid = false; //has full support of GET features in 4.0+ by using a new window. POST will resort to a POST on the current window. var isOtherMobileBrowser = false; //there is no way to reliably guess here so all other mobile devices will GET and POST to the current window. if (/ip(ad|hone|od)/.test(userAgent)) { isIos = true; } else if (userAgent.indexOf('android') != -1) { isAndroid = true; } else { isOtherMobileBrowser = /avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|playbook|silk|iemobile|iris|kindle|lge |maemo|midp|mmp|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|symbian|treo|up\.(browser|link)|vodafone|wap|windows (ce|phone)|xda|xiino/i.test(userAgent) || /1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|e\-|e\/|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(di|rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|xda(\-|2|g)|yas\-|your|zeto|zte\-/i.test(userAgent.substr(0, 4)); } var httpMethodUpper = settings.httpMethod.toUpperCase(); if (isAndroid && httpMethodUpper != "GET") { //the stock android browser straight up doesn't support file downloads initiated by non GET requests: http://code.google.com/p/android/issues/detail?id=1780 if ($().dialog) { $("<div>").html(settings.androidPostUnsupportedMessageHtml).dialog(settings.dialogOptions); } else { alert(settings.androidPostUnsupportedMessageHtml); } return; } //wire up a jquery dialog to display the preparing message if specified var $preparingDialog = null; if (settings.preparingMessageHtml) { $preparingDialog = $("<div>").html(settings.preparingMessageHtml).dialog(settings.dialogOptions); } var internalCallbacks = { onSuccess: function (url) { //remove the perparing message if it was specified if ($preparingDialog) { $preparingDialog.dialog('close'); }; settings.successCallback(url); }, onFail: function (responseHtml, url) { //remove the perparing message if it was specified if ($preparingDialog) { $preparingDialog.dialog('close'); }; //wire up a jquery dialog to display the fail message if specified if (settings.failMessageHtml) { $("<div>").html(settings.failMessageHtml).dialog(settings.dialogOptions); //only run the fallcallback if the developer specified something different than default //otherwise we would see two messages about how the file download failed if (settings.failCallback != defaultFailCallback) { settings.failCallback(responseHtml, url); } } else { settings.failCallback(responseHtml, url); } } }; //make settings.data a param string if it exists and isn't already if (settings.data !== null && typeof settings.data !== "string") { settings.data = $.param(settings.data); } var $iframe, downloadWindow, formDoc, $form; if (httpMethodUpper === "GET") { if (settings.data !== null) { //need to merge any fileUrl params with the data object var qsStart = fileUrl.indexOf('?'); if (qsStart != -1) { //we have a querystring in the url if (fileUrl.substring(fileUrl.length - 1) !== "&") { fileUrl = fileUrl + "&"; } } else { fileUrl = fileUrl + "?"; } fileUrl = fileUrl + settings.data; } if (isIos || isAndroid) { downloadWindow = window.open(fileUrl); downloadWindow.document.title = settings.popupWindowTitle; window.focus(); } else if (isOtherMobileBrowser) { window.location(fileUrl); } else { //create a temporary iframe that is used to request the fileUrl as a GET request $iframe = $("<iframe>") .hide() .attr("src", fileUrl) .appendTo("body"); } } else { var formInnerHtml = ""; if (settings.data !== null) { $.each(settings.data.replace(/\+/g, ' ').split("&"), function () { var kvp = this.split("="); var key = settings.encodeHTMLEntities ? htmlSpecialCharsEntityEncode(decodeURIComponent(kvp[0])) : decodeURIComponent(kvp[0]); if (!key) return; var value = kvp[1] || ''; value = settings.encodeHTMLEntities ? htmlSpecialCharsEntityEncode(decodeURIComponent(kvp[1])) : decodeURIComponent(kvp[1]); formInnerHtml += '<input type="hidden" name="' + key + '" value="' + value + '" />'; }); } if (isOtherMobileBrowser) { $form = $("<form>").appendTo("body"); $form.hide() .attr('method', settings.httpMethod) .attr('action', fileUrl) .html(formInnerHtml); } else { if (isIos) { downloadWindow = window.open("about:blank"); downloadWindow.document.title = settings.popupWindowTitle; formDoc = downloadWindow.document; window.focus(); } else { $iframe = $("<iframe style='display: none' src='about:blank'></iframe>").appendTo("body"); formDoc = getiframeDocument($iframe); } formDoc.write("<html><head></head><body><form method='" + settings.httpMethod + "' action='" + fileUrl + "'>" + formInnerHtml + "</form>" + settings.popupWindowTitle + "</body></html>"); $form = $(formDoc).find('form'); } $form.submit(); } //check if the file download has completed every checkInterval ms setTimeout(checkFileDownloadComplete, settings.checkInterval); function checkFileDownloadComplete() { //has the cookie been written due to a file download occuring? if (document.cookie.indexOf(settings.cookieName + "=" + settings.cookieValue) != -1) { //execute specified callback internalCallbacks.onSuccess(fileUrl); //remove the cookie and iframe var date = new Date(1000); document.cookie = settings.cookieName + "=; expires=" + date.toUTCString() + "; path=" + settings.cookiePath; cleanUp(false); return; } //has an error occured? //if neither containers exist below then the file download is occuring on the current window if (downloadWindow || $iframe) { //has an error occured? try { var formDoc; if (downloadWindow) { formDoc = downloadWindow.document; } else { formDoc = getiframeDocument($iframe); } if (formDoc && formDoc.body != null && formDoc.body.innerHTML.length > 0) { var isFailure = true; if ($form && $form.length > 0) { var $contents = $(formDoc.body).contents().first(); if ($contents.length > 0 && $contents[0] === $form[0]) { isFailure = false; } } if (isFailure) { internalCallbacks.onFail(formDoc.body.innerHTML, fileUrl); cleanUp(true); return; } } } catch (err) { //500 error less than IE9 internalCallbacks.onFail('', fileUrl); cleanUp(true); return; } } //keep checking... setTimeout(checkFileDownloadComplete, settings.checkInterval); } //gets an iframes document in a cross browser compatible manner function getiframeDocument($iframe) { var iframeDoc = $iframe[0].contentWindow || $iframe[0].contentDocument; if (iframeDoc.document) { iframeDoc = iframeDoc.document; } return iframeDoc; } function cleanUp(isFailure) { setTimeout(function() { if (downloadWindow) { if (isAndroid) { downloadWindow.close(); } if (isIos) { if (isFailure) { downloadWindow.focus(); //ios safari bug doesn't allow a window to be closed unless it is focused downloadWindow.close(); } else { downloadWindow.focus(); } } } }, 0); } function htmlSpecialCharsEntityEncode(str) { return str.replace(/&/gm, '&') .replace(/\n/gm, " ") .replace(/\r/gm, " ") .replace(/</gm, '<') .replace(/>/gm, '>') .replace(/"/gm, '"') .replace(/'/gm, '''); //single quotes just to be safe } } });