an easy way to select all mails in basic HTML view of Gmail
// ==UserScript==
// @name 'Select all' in Basic HTML View in Gmail
// @namespace http://vaxquis.tk
// @version 0.1
// @description an easy way to select all mails in basic HTML view of Gmail
// @author vaxquis
// @match https://mail.google.com/*
// @grant none
// ==/UserScript==
(function() {
'use strict';
const target = document.querySelector('form[name=f] table td');
const button = document.createElement('BUTTON');
const text = document.createTextNode('Select all');
button.style.marginRight = '1rem';
button.appendChild( text );
button.onclick = () => {
document.querySelectorAll('input[name=t]').forEach( t => { t.checked = true; } );
return false;
}
target.insertBefore(button, target.children[0]);
})();