How to track what domain name you are on and issue an alert to JS?

Question

JavaScript

How to track what domain name you are on and issue an alert on JS or jQuery ?

For example, on the test.ru domain issue alert('1') and here subdomen.test.ru issue alert('2')

Answer 1

var a=document.domain;
        if(a=="test.ru"){

alert(1)
}elseif(a=="poddomen.test.ru"){
alert(2)
}