How i can get the domain name example.com from the set of possible subdomains sub1.example.com sub2.example.com sub3.example.com
The generic solution is explained here http://rossscrivener.co.uk/blog/javascript-get-domain-exclude-subdomain From above link
var domain = (function(){
var i=0,domain=document.domain,p=domain.split('.'),s='_gd'+(new Date()).getTime();
while(i<(p.length-1) && document.cookie.indexOf(s+'='+s)==-1){
domain = p.slice(-1-(++i)).join('.');
document.cookie = s+"="+s+";domain="+domain+";";
}
document.cookie = s+"=;expires=Thu, 01 Jan 1970 00:00:01 GMT;domain="+domain+";";
return domain;
})();