php - Tool Suggest Top-Level Domains -

i creating tool our customers check if domain name exists. plan on using gethostbyname($domain) function. but, want pre-program other tld's checked along preferred tld (sent through form). don't know start here included example below user suggestions.

    // supported top-level domain names (tlds) $tld['coming_soon'] = ".realty, .construction";  $tld['current']     = ".com, .org, .us";      // receive form data , strip tags  $source =   $_server['http_referer']; $domain =   strip_tags($_post['domain_name']); $tld    =   strip_tags($_post['tld']); $req    =   $domain.$tld;      // check client's preferred domain      if ( gethostbyname($req) != $req ) {       echo "dns record found";      } else {       echo "no dns record found";     }       // do: check alternative top-level domains       // do: somehow search through $tld array, compare, , give result 

gethostbyname($domain) not sufficient; tell if domain active, not whether available purchase or not.

to find out whether it's available buy, need query relevant whois service each domain type. differ each domain type, , parsing resulting data can pain, better off using api

the registrars you're using register domains should able provide api can call. contact them , find out have , how use it. that's best option.