Js点击按钮下载文件到本地（兼容多浏览器）

实现点击 用纯 js(非jquery)  下载文件到本地 

自己尝试，加网上找了好久未果，如：

window.open(url)   location.href=url   form表单提交   iframe  体验和浏览器兼容都不完美

还是博客园一兄弟给了方法，非常感谢！

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;