[рони]

Slandewi,

gotosite.click(function(){
    var text = document.getElementById('txt').value;
    if (text.indexOf('yandex') !== -1) {
        location.href="https://yandex.ru";
    } else if (text.indexOf('google') !== -1) {
        location.href="https://google.com";
    } else {
        alert("Whoops, something went wrong...");
    }
});