file download javascript

download.js

function download(url, filename){
    var xhr = new XMLHttpRequest(),
          a = document.createElement('a'), file;
    
    xhr.open('GET', url, true);
    xhr.responseType = 'blob';
    xhr.onload = function () {
        file = new Blob([this.response], { type : 'application/octet-stream' });
        a.href = window.URL.createObjectURL(file);
        a.download = filename;
        a.click();
    };
    xhr.send();
}