PHP Custom Function Gets the first-level domain name in the URL _php tips

This article illustrates how PHP custom functions get the first-level domain name in a URL. Share to everyone for your reference, specific as follows:

<?php * * Created on 2016-8-23/function Regular_domain ($domain) {if (substr ($domain, 0, 7) = = ' http://') {
  $domain = substr ($domain, 7);
  } if (Strpos ($domain, '/')!== false) {$domain = substr ($domain, 0, Strpos ($domain, '/'));
Return Strtolower ($domain);
  The function Top_domain ($domain) {$domain = Regular_domain ($domain);
      $iana _root = Array (' AC ', ' ad ', ' AE ', ' aero ', ' AF ', ' AG ', ' ai ', ' al ',
      ' AM ', ' a ', ' ao ', ' aq ', ' ar ', ' arpa ', ' as ', ' Asia ', ' at ', ' au ',
      ' AW ', ' ax ', ' az ', ' ba ', ' BB ', ' BD ', ' be ', ' bf ', ' bg ', ' BH ',
      ' Bi ', ' biz ', ' bj ', ' bl ', ' bm ', ' bn ', ' bo ', ' Bq ', ' BR ', ' BS ',
      ' BT ', ' BV ', ' bw ', ' by ', ' BZ ', ' Ca ', ' Cat ', ' cc ', ' CD ', ' CF ',
  ' CG ',    ' ch ', ' ci ', ' ck ', ' cl ', ' cm ', ' cn ', ' Co ', ' com ', ' coop ', ' CR ',
      ' cu ', ' CV ', ' CW ', ' CX ', ' Cy ', ' cz ', ' de ', ' DJ ', ' DK ', ' DM ',
      ' Do ', ' dz ', ' ec ', ' edu ', ' ee ', ' eg ', ' eh ', ' er ', ' es ', ' et ',
      ' EU ', ' fi ', ' fj ', ' FK ', ' FM ', ' fo ', ' fr ', ' GA ', ' GB ', ' GD ', ' GE ', ' gf ', ' gg ', ' gh ', ' gi ', ' gl ', ' GM ', ' gn ', ' gov ', ' GP ', ' GQ ', ' gr ', ' GS ', ' gt ', ' gu ', ' GW ', ' Gy ', ' HK ', ' HM ', ' HN ', ' HR ', ' HT ', ' Hu ', ' id ', ' ie ', ' il ', ' im ', ' in ', ' info ', ' int ', ' I O ', ' IQ ', ' ir ', ' is ', ' it ', ' je ', ' jm ', ' Jo ', ' Jobs ', ' JP ', ' K E ', ' kg ', ' Kh ', ' Ki ', ' km ', ' kn ', ' kp ', ' kr ', ' kw ', ' ky ', ' kz ', ' la ', ' lb '
      , ' LC ', ' Li ', ' lk ', ' lr ', ' ls ', ' lt ', ' Lu ', ' LV ', ' ly ', ' ma ',
      ' MC ', ' MD ', ' Me ', ' mf ', ' mg ', ' mh ', ' Mil ', ' mk ', ' ml ', ' mm ', ' mn ', ' Mo ', ' mobi ', ' MP ', ' MQ ', ' Mr ', ' Ms ', ' Mt ', ' mu ', ' Museum ', ' mv ', ' MW ', ' mx ', ' my ', ' mz ', ' na ', ' name ', ' NC ', ' ne ', ' NE T ', ' nf ', ' ng ', ' ni ', ' nl ', ' no ', ' NP ', ' nr ', ' Nu ', ' NZ ', ' Om ' 
      , ' org ', ' pa ', ' pe ', ' PF ', ' pg ', ' ph ', ' PK ', ' pl ', ' pm ', ' PN ',
      ' PR ', ' pro ', ' ps ', ' pt ', ' pw ', ' py ', ' QA ', ' re ', ' ro ', ' rs ',
' Ru ', ' RW ',      ' sa ', ' sb ', ' SC ', ' sd ', ' se ', ' sg ', ' sh ', ' si ', ' sj ', ' SK ',
      ' SL ', ' SM ', ' sn ', ' so ', ' SR ', ' SS ', ' St ', ' su ', ' SV ', ' SX ',
      ' Sy ', ' sz ', ' TC ', ' TD ', ' Tel ', ' tf ', ' TG ', ' th ', ' TJ ', ' TK ',
      ' TL ', ' TM ', ' TN ', ' to ', ' TP ', ' tr ', ' travel ', ' TT ', ' TV ', ' TW ',
      ' TZ ', ' ua ', ' ug ', ' UK ', ' um ', ' us ', ' uy ', ' uz ', ' va ', ' VC ',
      ' ve ', ' VG ', ' vi ', ' vn ', ' vu ', ' wf ', ' ws ', ' xxx ', ' ye ', ' yt ',
  ' Za ', ' zm ', ' ZW ');
  $sub _domain = Explode ('. ', $domain);
  $top _domain = ';
  $top _domain_count = 0; for ($i = count ($sub _domain)-1; $i >= 0; $i-} {if ($i = = 0) {//Just in case of something like name.c
    OM break;
 }   if (In_array ($sub _domain [$i], $iana _root)) {$top _domain_count + +; $top _domain = '. ' $sub _domain [$i].
      $top _domain;
      if ($top _domain_count >= 2) {break; $top _domain = $sub _domain [count ($sub _domain)-$top _domain_count-1].
  $top _domain;
return $top _domain;

 Echo Top_domain ("http://tools.jb51.net/");?>

The results of the operation are:

More about PHP Interested readers can view the site topics: "PHP Regular Expression Usage summary", "Php Curl Usage Summary", "PHP Array" operation Skills Encyclopedia, "PHP Sorting algorithm Summary", "PHP common traversal algorithm and skills summary", " PHP Data structure and algorithm tutorial, "PHP Programming Algorithm Summary", "PHP Mathematical Calculation Skills Summary", "PHP operation and operator Usage Summary", "PHP string (String) Usage summary" and "PHP common database Operation Skills Summary"

I hope this article will help you with the PHP program design.