tt-rss/plugins/mailto/init.js

function mailtoArticle(id) {
	if (!id) {
		const ids = Headlines.getSelected();

		if (ids.length == 0) {
			alert(__("No articles selected."));
			return;
		}

		id = ids.toString();
	}

	if (dijit.byId("emailArticleDlg"))
		dijit.byId("emailArticleDlg").destroyRecursive();

	const query = "backend.php?op=pluginhandler&plugin=mailto&method=emailArticle&param=" + encodeURIComponent(id);

	const dialog = new dijit.Dialog({
		id: "emailArticleDlg",
		title: __("Forward article by email"),
		style: "width: 600px",
		href: query});

	dialog.show();
}