[jquery] How to get Domain name from URL using jquery..?

You don't need jQuery for this, as simple javascript will suffice:

alert(document.domain);

See it in action:

console.log("Output;");  
console.log(location.hostname);
console.log(document.domain);
alert(window.location.hostname)

console.log("document.URL : "+document.URL);
console.log("document.location.href : "+document.location.href);
console.log("document.location.origin : "+document.location.origin);
console.log("document.location.hostname : "+document.location.hostname);
console.log("document.location.host : "+document.location.host);
console.log("document.location.pathname : "+document.location.pathname);

for more details click here window.location

just append "http://" before domain name to get appropriate result.