JS
(quick guide & examples)
var first = "car"; var second = "CAR";
if (first.toLowerCase() == second.toLowerCase()) { SAME }
if (first.toUpperCase() == second.toUpperCase()) { SAME }
if (first.localeCompare( second, "en", sensitivity: "base" } ) == 0) { SAME }
var first = "car"; var second = "CAR";
var first = "CAR"; var pattern = /^car$/i;
if (pattern.test(first)) { SAME }