As explained in some threads, Internet Explorer adds some invisible extra characters when returning a date from the JavaScript function new Intl.DateTimeformat. var day = « Thursday »; var intlDay = new Intl.DateTimeFormat(‘en-US’, {weekday: »long »}).format(new Date(2019,1,7)); console.log(day === intlDay); // return FALSE with IE intlDay = intlDay.replace(/\u200E/g, »); // replace \u200E console.log(day === intlDay); // return TRUE with […]