点击文件下载

function downloadFile(fileName, content){
    var aLink = document.createElement('a');
    var blob = new Blob([content]);
    var evt = document.createEvent("HTMLEvents");
    evt.initEvent("click", false, false);//initEvent 不加后两个参数在FF下会报错, 感谢 Barret Lee 的反馈
    aLink.download = fileName;
    aLink.href = URL.createObjectURL(blob);
    aLink.dispatchEvent(evt);
}