JavaScript regular expression validation for domain name?

Question

How to check a valid domain name and username with regular expression in JavaScript?

function validate()
{
    var         


        

Answer 1

This maybe slightly off-topic but after searching the internet for several hours and trying out various RegExp's (non of which would work for me). I decided to write my own function that would take a list of valid TLD extensions and run a validation against them. So for anyone who is having a similar problem, please check out my Javascript function:

function domainCheck(dom) {
    // convert input to lowercase.
    dom = dom.toLowerCase();
    // find the first occurance of '.'
    pos = dom.indexOf(".");
    // Using the first occurance of '.'
    // find the extension submitted.
    tld = dom.substring(pos);
    switch(tld) {
        // TLD's to accept.
        case '.com': return true; break;
        case '.co.uk': return true; break;
        case '.eu': return true; break;
        case '.io': return true; break;
        case '.co': return true; break;
        case '.net': return true; break;
        default: return false;
    }
}

I have created a demo using this function here: http://jsfiddle.net/netfox/MhPG8/19/embedded/result/