gistfile1.txt

(()=>{
let rgxEmail = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{1,3})+$/;
let t1 = Date.now();
let passTest = rgxEmail.test('abcdefghijklmnopqrstuvwxyza');
let ms = Date.now() - t1;
alert(ms);
})()
// 132 ms stopping at 24 chars
// 245 ms when stopping at 25 chars
// 484 ms when at 26 chars
// 1046 ms when at 27 chars
// 35916 ms(!) at 28 chars