REGEX where img tag does not have alt

Question

I am trying to write a regex that looks for an img tag where there is no alt attribute.

Here is the regex.

<img\s+src.+^(?!alt).+$

Here are some samples

<img src="smiley.gif" alt="Smiley face" height="42" width="42">
<img src="smiley2.gif" height="42" width="42">
<img src="smiley3.gif" alt="Smiley face Three" height="42" width="42">

Here is a link to regex101 https://regex101.com/r/Z5vkQb/3/

score 2 · Answer 1 · answered Apr 02 '19 at 17:09

Don't.

You haven't specified which language you're using, but chances are good you have a DOM parser available.

For example, in JavaScript, you can just do this:

var imgs_with_no_alt = document.querySelectorAll("img:not([alt])");

In PHP you would need something like this:

$dom = new DOMDocument();
$dom->loadHTML("your HTML here");
$images = $dom->getElementsByTagName("img");
foreach($images as $image) {
    if( $image->getAttribute("alt")) continue;
    // do something to $image here, which doesn't have an [alt] attribute
}

score 1 · Accepted Answer · answered Apr 02 '19 at 17:08

1

If within the same line, you can use this,

<img(?!.*\s+alt\s*=).+$

Demo

answered Apr 02 '19 at 17:08

Pushpesh Kumar Rajwanshi

18,127
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`` - Using regex to parse HTML ***does not work!!!*** – Niet the Dark Absol May 12 '19 at 19:14

Wilmer · Answer 3 · 2019-04-02T17:08:49.633

0

You can use this expression:

<img[^>]*alt=[^>]*>

edited Apr 02 '19 at 17:08

answered Apr 02 '19 at 17:06

Wilmer

138
1
8

`` makes you salty because your expression fails. – Niet the Dark Absol Apr 02 '19 at 17:07
Include the `=` after the `alt`. e.g. `]*alt=[^>]*>` – Wilmer Apr 02 '19 at 17:08
`` – Niet the Dark Absol Apr 02 '19 at 17:10
`]*\s+alt=[^>]*>` – Wilmer Apr 02 '19 at 17:15
`` – Niet the Dark Absol Apr 02 '19 at 18:00

REGEX where img tag does not have alt

3 Answers3