Regular expression for grabbing the href attribute of an A element

Question

Hi there

Trying to find the links on a page.

my regex is:

/<a\s[^>]*href=(\"\'??)([^\"\' >]*?)[^>]*>(.*)<\/a>/

but seems to fail at

<a title="this" href="that">what?</a>

how would I change my regex to deal with href not placed first in the a tag?

thanks!

Answer 1

why don't you just match

"<a.*?href\s*=\s*['"](.*?)['"]"

<?php

$str = '<a title="this" href="that">what?</a>';

$res = array();

preg_match_all("/<a.*?href\s*=\s*['\"](.*?)['\"]/", $str, $res);

var_dump($res);

?>

then

$ php test.php
array(2) {
  [0]=>
  array(1) {
    [0]=>
    string(27) "<a title="this" href="that""
  }
  [1]=>
  array(1) {
    [0]=>
    string(4) "that"
  }
}

which works. I've just removed the first capture braces.

Answer 2

The pattern you want to look for would be the link anchor pattern, like (something):

$regex_pattern = "/<a href=\"(.*)\">(.*)<\/a>/";

Answer 3

I made a test here http://www.spaweditor.com/scripts/regex/index.php. It finds regex, just remove semicolon. What is your intention?

Answer 4

Quick test: <a\s+[^>]*href=(\"\'??)([^\1]+)(?:\1)>(.*)<\/a> seems to do the trick, with the 1st match being " or ', the second the 'href' value 'that', and the third the 'what?'.

The reason I left the first match of "/' in there is that you can use it to backreference it later for the closing "/' so it's the same.

See live example on: http://www.rubular.com/r/jsKyK2b6do

Answer 5

I'm not sure what you're trying to do here, but if you're trying to validate the link then look at PHP's filter_var()

If you really need to use a regular expression then check out this tool, it may help: http://regex.larsolavtorvik.com/

Answer 6

Using your regex, I modified it a bit to suit your need.

<a.*?href=("|')(.*?)("|').*?>(.*)<\/a>

I personally suggest you use a HTML Parser

EDIT: Tested

Answer 7

HTML is not regular. Here is how to do it with DOM:

$dom = new DOMDocument;
$dom->loadHTML($html);
foreach( $dom->getElementsByTagName('a') as $node ) {
    echo $dom->saveXml($node), PHP_EOL;
}

The above would find and output the "outerHTML" of all A elements in the $html string.

To get the href attribute you'd do

echo $node->getAttribute( 'href' );

See the linked blog post for an alternate approach with XPath and further information on how to handle any errors stemming from invalid markup.

Also see:

• Best methods to parse HTML

On a sidenote: I am sure this is a duplicate and you can find the answer somewhere in here

Answer 8

I agree with Gordon, you MUST use an HTML parser to parse HTML. But if you really want a regex you can try this one :

/^<a.*?href=(["\'])(.*?)\1.*$/

This matches <a at the begining of the string, followed by any number of any char (non greedy) .*? then href= followed by the link surrounded by either " or '

$str = '<a title="this" href="that">what?</a>';
preg_match('/^<a.*?href=(["\'])(.*?)\1.*$/', $str, $m);
var_dump($m);

Output:

array(3) {
  [0]=>
  string(37) "<a title="this" href="that">what?</a>"
  [1]=>
  string(1) """
  [2]=>
  string(4) "that"
}