PHP gets all the link examples in the specified URL page

The following code can get all the links in the specified URL page, that is, the href attribute of all a tags:

Get the linked HTML code
$html = file_get_contents (' http://www.111cn.net ');

$dom = new DOMDocument ();
@ $dom->loadhtml ($html);

$xpath = new Domxpath ($dom);
$hrefs = $xpath->evaluate ('/html/body//a ');

for ($i = 0; $i < $hrefs->length; $i + +) {
$href = $hrefs->item ($i);
$url = $href->getattribute (' href ');
echo $url. ' <br/> ';
}

This code gets the href attribute of all a tags, but the href attribute value is not necessarily a link, so we can filter it and keep only the URL at the beginning of the http:

Get the linked HTML code
$html = file_get_contents (' http://www.111cn.net ');

$dom = new DOMDocument ();
@ $dom->loadhtml ($html);

$xpath = new Domxpath ($dom);
$hrefs = $xpath->evaluate ('/html/body//a ');

for ($i = 0; $i < $hrefs->length; $i + +) {
$href = $hrefs->item ($i);
$url = $href->getattribute (' href ');

Keep a link that starts with HTTP
if (substr ($url, 0, 4) = = ' http ')
echo $url. ' <br/> ';
}

fopen () function read all the links in the specified Web page and count the number, in some need to collect page page content, suitable for use this code, this example to read Baidu home page For example, find all the link address Baidu home page, the code has been tested, fully available:

;?
if (empty ($url)) $url = "http://www.baidu.com/";//need to collect the URL address of the link
$site =substr ($url, 0,strpos ($url, "/", 8));
$base =substr ($url, 0,strrpos ($url, "/") +1)//file directory
$fp = fopen ($url, "R");//Open URL Address page
while (!feof ($FP)) $ Contents.=fread ($FP, 1024);
$pattern = "|href=['"]? ([^ '\"]+) ['\" ]| U ";
Preg_match_all ($pattern, $contents, $REGARR, preg_set_order);//use a regular match for all href=
for ($i =0; $i <count ($REGARR) ; $i + +) {//Find all matching links
if (!eregi (":/", $REGARR [$i][1])//To determine if there is a relative path, that is, whether there are also://
    if substr ($ regarr[$i][1],0,1) = =//is the root of the site
    echo "link". ( $i + 1). ":". $site. $regArr [$i][1]. " <br/>//Root
    else
    echo "link". ( $i + 1). ":". $base. $regArr [$i][1]. " <br/>//Current directory
Else
    echo "link". ( $i + 1). ":". $regArr [$i][1]. " <br/>//relative path
}
fclose ($fp);
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