Replace Content in PRE Tags with HTML Entities
If you have a website that relies heavily on PRE tags, you know the important of converting PRE tag content to their HTML entities. Doing so prevents worlds of possible rendering issues. The following PHP snippet HTML-Entitizes (?) any code within PRE tags:
//replaces pre content with html entities
function pre_entities($matches) {
return str_replace($matches[1],htmlentities($matches[1]),$matches[0]);
}
//to html entities; assume content is in the "content" variable
$content = preg_replace_callback('/<pre.*?>(.*?)<\/pre>/imsu',pre_entities, $content);
I use this for just about every post I write. You could also stick this in your CMS if you have clients that may have use for PRE tags.
![CSS Filters]()
CSS filter support recently landed within WebKit nightlies. CSS filters provide a method for modifying the rendering of a basic DOM element, image, or video. CSS filters allow for blurring, warping, and modifying the color intensity of elements. Let's have...
![39 Shirts – Leaving Mozilla]()
In 2001 I had just graduated from a small town high school and headed off to a small town college. I found myself in the quaint computer lab where the substandard computers featured two browsers: Internet Explorer and Mozilla. It was this lab where I fell...
![Create a Quick MooTools Slideshow with Preloading Images]()
I've been creating a lot of slideshow posts lately. Why, you ask? Because they help me get chicks. A quick formula for you:
The following code snippet will show you how to create a simple slideshow with MooTools; the script will also...
![Spatial Navigation]()
Spatial navigation is the ability to navigate to focusable elements based on their position in a given space. Spatial navigation is a must when your site or app must respond to arrow keys, a perfect example being a television with directional pad remote. Firefox OS TV apps are simply...
Beware that having someting like “something” in another would leave you with one opening and two closings. If this is a possible usecase, you might use a regex like this :
/(.*?[.*]*)/imsu
…but it still wouldn’t handle the case of having a single closing tag inside another . Could someone manage to write a regex which would handle this case ?
The function name (pre_entities) should be between quotes otherwise it will throw a notice.
Beware that having a pre tag inside another pre tag would leave you with one pre opening and two pre closings. If this is a possible usecase, you might use a regex like this :
/<pre.*?>(.*?[<pre.*?>.*<\/pre>]*)<\/pre>/imsu
The tags got stripped in my first comment, sorry about that, if htmlentities show up in the regex, replace them with the good characters …but it still wouldn’t handle the case of having a single closing pre tag inside another pre. Could someone manage to write a regex which would handle this case ?
The function name (pre_entities) should be between quotes otherwise it will throw a notice.
It works as long as you don’t have nested <pre> tags.
I wrote about this on my blog but the only real way to do it is to use an XML parser.
One issue to watch out for is to not encode any of the content before this is run, as it will double-entitize the ampersand e.g., &.
Also, would there be any issues if not matches are found?
To solve the nested ‘pre’ tag issue, just use some non-standard tags that you’re sure won’t be in your content, rather than ‘pre’ (i.e. ‘mycode’). Your regular expression then becomes a match for the ‘mycode’ tags, and you can immediately follow it up with another preg_replace () to turn the ‘mycode’ tags into ‘pre’ tags after you’re done htmlentitizing the content.
I’ve been using elliotswan.com/postable. It seems to get the job done for me. But it’s nice to know this option.
Could someone explain how to fix the following notice?
Notice: Use of undefined constant pre_entities – assumed ‘pre_entities’ in C:\wamp\www\example.com\admin\get_posts.php on line 16
doh! put quotes on ‘pre_entities’, fixes it. Thanks David! Great snippet.
Thank you for the tip! I couldn’t find what was going wrong with the HTML…