<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<script type="text/javascript" src="../js/jquery-1.11.1.min.js"></script>
<script type="text/javascript">
function downloadFile(fileName, content){
var aLink = document.createElement(‘a‘);
var blob = new Blob([content]);
//var evt = document.createEvent("HTMLEvents");firefox不支持
var evt = document.createEvent("MouseEvents"); //firefox、chrome都支持
aLink.download = fileName;
aLink.href = URL.createObjectURL(blob);
aLink.textContent = "Download Hello World!";
//evt.initMouseEvent(‘click‘, true, true, window, 0, 0, 0, 0, 0, false, false, false, false, 0, aLink);//网友提出的方法不可行
evt.initEvent("click", true, true);//initEvent 不加后两个参数在FF下会报错
document.body.appendChild(aLink);
aLink.dispatchEvent(evt);
}
</script>
</head>
<body>
<input type="button" onclick="downloadFile(‘1.txt‘,‘hello world!‘)" />
</body>
</html>
原文：http://www.cnblogs.com/shysky77/p/4912707.html