JavaScript function to trigger file download within the browser.

browser-file-download.js

/**
 * Triggers browser to download a file with content.
 * 
 * Accomplishes by creating a temporary a tag that we encode filename and data to and then click on behalf of user.
 * 
 * @example
 * browserFileDownload("results.txt","Success Example!");
 * @example
 * browserFileDownload("example.xml", "<?xml version=\"1.0\" encoding=\"UTF-8\"?><collection><item>1</item></collection>", "application/xml");
 * 
 * @param {string} filename - The filename with extension of the download we want to create and download.
 * @param {string} content - The file contents to be encoded for download.
 * @param {string} type [type=text/plain] - The type of file encoding (MIME_TYPE).
 *  @see https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types
 * @param {string} charset [charset=utf-8] - The character set of the file encoding.
 */
function browserFileDownload(filename, content, type = 'text/plain', charset = 'utf-8') {
  var link = document.createElement('a');

  link.href = 'data:' + type + ';charset=' + charset + ',' + encodeURIComponent(content);
  link.download = filename;

  link.click();
}