在客户端通过js下载文件，试过几种下载方式，iframe方式仅限于IE浏览器，window.open(url)，location.href=url 这两种方式在chrome浏览器还会是直接打开文件而不是下载，百度N久没有结果，在谷歌还是找到答案了，下载链接在此。
window.downloadFile = function (sUrl) { //iOS devices do not support downloading. We have to inform user about this. if (/(iP)/g.test(navigator.userAgent)) { alert(\'Your device does not support files downloading. Please try again in desktop browser.\'); return false; } //If in Chrome or Safari - download via virtual link click if (window.downloadFile.isChrome || window.downloadFile.isSafari) { //Creating new link node. var link = document.createElement(\'a\'); link.href = sUrl; if (link.download !== undefined) { //Set HTML5 download attribute. This will prevent file from opening if supported. var fileName = sUrl.substring(sUrl.lastIndexOf(\'/\') + 1, sUrl.length); link.download = fileName; } //Dispatching click event. if (document.createEvent) { var e = document.createEvent(\'MouseEvents\'); e.initEvent(\'click\', true, true); link.dispatchEvent(e); return true; } } // Force file download (whether supported by server). if (sUrl.indexOf(\'?\') === -1) { sUrl += \'?download\'; } window.open(sUrl, \'_self\'); return true; } window.downloadFile.isChrome = navigator.userAgent.toLowerCase().indexOf(\'chrome\') > -1; window.downloadFile.isSafari = navigator.userAgent.toLowerCase().indexOf(\'safari\') > -1;