Simple solution for HTML5 ready browsers…
function download(filename, text) {
var pom = document.createElement('a');
pom.setAttribute('href', 'data:text/plain;charset=utf-8,' + encodeURIComponent(text));
pom.setAttribute('download', filename);
if (document.createEvent) {
var event = document.createEvent('MouseEvents');
event.initEvent('click', true, true);
pom.dispatchEvent(event);
}
else {
pom.click();
}
}
Usage
download('test.txt', 'Hello world!');