Strip all HTML attributes except for src
Solution 1
Alright, here's what I used that seems to be working well:
<([A-Z][A-Z0-9]*)(\b[^>src]*)(src\=[\'|"|\s]?[^\'][^"][^\s]*[\'|"|\s]?)?(\b[^>]*)>
Feel free to poke any holes in it.
Solution 2
This might work for your needs:
$text = '<p id="paragraph" class="green">This is a paragraph with an image <img src="/path/to/image.jpg" width="50" height="75"/></p>';
echo preg_replace("/<([a-z][a-z0-9]*)(?:[^>]*(\ssrc=['\"][^'\"]*['\"]))?[^>]*?(\/?)>/i",'<$1$2$3>', $text);
// <p>This is a paragraph with an image <img src="/path/to/image.jpg"/></p>
The RegExp broken down:
/ # Start Pattern
< # Match '<' at beginning of tags
( # Start Capture Group $1 - Tag Name
[a-z] # Match 'a' through 'z'
[a-z0-9]* # Match 'a' through 'z' or '0' through '9' zero or more times
) # End Capture Group
(?: # Start Non-Capture Group
[^>]* # Match anything other than '>', Zero or More Times
( # Start Capture Group $2 - ' src="...."'
\s # Match one whitespace
src= # Match 'src='
['"] # Match ' or "
[^'"]* # Match anything other than ' or "
['"] # Match ' or "
) # End Capture Group 2
)? # End Non-Capture Group, match group zero or one time
[^>]*? # Match anything other than '>', Zero or More times, not-greedy (wont eat the /)
(\/?) # Capture Group $3 - '/' if it is there
> # Match '>'
/i # End Pattern - Case Insensitive
Add some quoting, and use the replacement text <$1$2$3> it should strip any non src= properties from well-formed HTML tags.
Please Note This isn't necessarily going to work on ALL input, as the Anti-HTML + RegExp people are so cleverly noting below. There are a few fallbacks, most notably <p style=">"> would end up <p>"> and a few other broken issues... I would recommend looking at Zend_Filter_StripTags as a full proof tags/attributes filter in PHP
Solution 3
You usually should not parse HTML using regular expressions.
Instead, you should call DOMDocument::loadHTML.
You can then recurse through the elements in the document and call removeAttribute.
Ian McIntyre Silber
Updated on June 05, 2022Comments
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Ian McIntyre Silber about 2 years
I'm trying to remove all tag attributes except for the
srcattribute. For example:<p id="paragraph" class="green">This is a paragraph with an image <img src="/path/to/image.jpg" width="50" height="75"/></p>Would be returned as:
<p>This is a paragraph with an image <img src="/path/to/image.jpg" /></p>I have a regular expression to strip all attributes, but I'm trying to tweak it to leave in
src. Here's what I have so far:<?php preg_replace('/<([A-Z][A-Z0-9]*)(\b[^>]*)>/i', '<$1>', '<html><goes><here>');