regexp help - get html tag attribute value

- 78 Posts
tjalve Reply #1, 19 years, 7 months ago
Hi, I’m using FeedX for reading comic strip feeds and send the image from the feed to a javascript that use .innerHTML to swap images in a div.

From a certain type of feeds the image comes packed inside HTML, which I can’t send directly to the javascript, so I need to parse it and get the content of the img src attribute only.

Specifically, I’ll get the image to a FeedX placeholder ’[+DESCRIPTION+]’ typically containing a string like this:
```
<img src="http://spray.nettavisen.no/shared/nemi/img/04.10.06.gif" border="0" />
```
and need to parse it so I can send only this to the javascript:
```
http://spray.nettavisen.no/shared/nemi/img/04.10.06.gif
```
To do this, I’ve installed PHx and made a snippet ’phx:imgsrc’ like this:
```
<?php
$pattern = '\"(.+?)\"';
preg_match($pattern,$output,$matches);
return $matches[0];
?>
```
I’ve tested the regexp in Komodo Rx Toolkit and it matches. I’ve also tested PHx and it works correctly.

However when I try to use this modifier on the placeholder like this: ’[+DESCRIPTION:imgsrc+]’ I get this error:
```
PHP error debug
  Error: 	preg_match() [function.preg-match]: Delimiter must not be alphanumeric or backslash	 
  Error type/ Nr.: 	Warning - 2
```
I’ve looked at a lot of online examples, and all uses backslashes to escape the double quote. I’ve tried a zillion different regular expressions but not managed to make a correct one!

How can I write a PHx modifier that will do what I want?
- 788 Posts
jesster444 Reply #2, 19 years, 7 months ago
I am not a regxp person, but you could probably use
```
function textBetween($s1,$s2,$s){
  $s1 = strtolower($s1);
  $s2 = strtolower($s2);
  $L1 = strlen($s1);
  $scheck = strtolower($s);

  if($L1>0){$pos1 = strpos($scheck,$s1);} else {$pos1=0;}
  if($pos1 !== false){
   if($s2 == '') return substr($s,$pos1+$L1);
   $pos2 = strpos(substr($scheck,$pos1+$L1),$s2);
   if($pos2!==false) return substr($s,$pos1+$L1,$pos2);
  }
  return '';
}
```
Then do something like textBetween("img src=", "/>", $output). Depending on what is actually being returned, you might have to replace some of those characters with the html entity that represents them.
Jesse R.
Consider trying something new and extraordinary.
Illinois Wine

Have you considered donating to MODx lately?
Donate now. Every contribution helps.