Close all HTML unclosed IMG tags

Question

Is it possible to do a regex replace on all IMG tags that are unclosed? If so, how would I identify:

  <img src="..." alt="...">

...as a potential canidate to be replaced?

   = <img src="..." alt="..."/>

Update: We have hundreds of pages, and thousands of image tags, all must of which must be closed. I'm not stuck on RegEx -- any other method, aside from manually updating all IMG tags, would suffice.

Answer 1

(<img[^>]+)(?<!/)>

will match an img tag that is not properly closed. It requires that the regex flavor you're using supports lookbehind (which Ruby and JavaScript don't but most others do). Backreference no. 1 will contain the match, so if you search for this regex and replace by \1/> you should be good to go.

If you need to account for the possibility of > inside attributes, you could use

(<img("[^"]*"|[^>])+)(?<!/)>

This will match, e.g.,

<img src="image.gif" alt="hey, look--->">
<img src="image/image.gif">

and leave

<img src="image/image.gif" />

alone.

Answer 2

In HTML the end tag for an <img> "must be omitted", so the start tag closes the element and you can't have an unclosed img.

If you want to convert your HTML to XHTML then use a real parser. Regular Expressions aren't a very good tool for this job.