There will come a time when you will have to know a url’s :

• Protocol
• Subdomain
• Domain
• Host
• Parent Domain
• TLD
• Path
• All of its query parameters

Let’s assume you want to parse below url:

https://demo.codewithmark.com/contact?id=123&name=mark

Its components would be:

• Protocol: https
• Domain: demo.codewithmark.com
• Host: codewithmark
• Parent Domain: codewithmark.com
• TLD: com
• Path : contact?id=123&name=mark
• Query String: id=123&name=mark

When You Should Parse URL

This url parsing will come in handy when you need to collect data from query string on page load for your client’s campaign ad to see how well it is doing.

Or

If you have a multi-user WordPress site and you want to add “nofollow” to all the external links.

Javascript Parse URL Function

function parseURL(url)
{
    parsed_url = {}

    if ( url == null || url.length == 0 )
        return parsed_url;

    protocol_i = url.indexOf('://');
    parsed_url.protocol = url.substr(0,protocol_i);

    remaining_url = url.substr(protocol_i + 3, url.length);
    domain_i = remaining_url.indexOf('/');
    domain_i = domain_i == -1 ? remaining_url.length - 1 : domain_i;
    parsed_url.domain = remaining_url.substr(0, domain_i);
    parsed_url.path = domain_i == -1 || domain_i + 1 == remaining_url.length ? null : remaining_url.substr(domain_i + 1, remaining_url.length);    

    domain_parts = parsed_url.domain.split('.');   

    switch ( domain_parts.length )
    {
        case 2:
          parsed_url.subdomain = null;
          parsed_url.host = domain_parts[0];
          parsed_url.tld = domain_parts[1];
          break;
        case 3:
          parsed_url.subdomain = domain_parts[0] == 'www' ?  null : domain_parts[0];
          parsed_url.host = domain_parts[1];
          parsed_url.tld = domain_parts[2];
          break;
        case 4:
          parsed_url.subdomain = domain_parts[0] == 'www' ?  null : domain_parts[0];
          parsed_url.host = domain_parts[1];
          parsed_url.tld = domain_parts[2] + '.' + domain_parts[3];
          break;
    }

    parsed_url.parent_domain = parsed_url.host + '.' + parsed_url.tld;


    function getUrlVars(url) 
    {   
        var decodedUrl = decodeURIComponent(url);
        var any_param = decodedUrl.indexOf('?'); 
        if(any_param >  0)
        {
             any_param = decodedUrl.slice(decodedUrl.indexOf('?') + 1);
            var hashes = any_param.split('&');
            
            var merged = {};
            var hash;        

            for(var i = 0; i < hashes.length; i++) 
            {
                var res = {};
                hash = hashes[i].split('=');  

                if(hash.length > 0)
                {
                    res[hash[0]] = hash[1];
                    Object.assign(merged, res );
                }
            }            
            if(hashes.length > 0)
            {
                return merged;    
            }
        }
        else
        {
            return null; 
        }
    }

    return Object.assign(parsed_url, {qry_str : getUrlVars(url)});
}

Below is the components of: https://demo.codewithmark.com/contact?id=123&name=mark

Demo

Once you click away from the above, below it will show components of your url

How To Use The URL Parser Function:

<script type="text/javascript">


var url = parseURL('https://demo.codewithmark.com/contact?id=123&name=mark');

//out put
console.log(url.domain) //demo.codewithmark.com

console.log(url.host) //codewithmark

console.log(url.qry_str.id) //123
 
</script>