Tutorials, PHP & MySQL

Strip tags from a string

From time to time you may need to remove certain tags from a string but leave other tags in tact, This tutorial will show you how to accomplish this.

You can use strip_tags() to remove all tags or specify which tags are allowed generally this is fine but what if you have a lot of different tags that you want to leave alone and only remove a one or more tags using strip_tags() you would need to specify every single tag you want to allow which can get very tiresome, a much better approach would be if you could simple say remove only the tags you specify.

There is no such function built into PHP to do that but making your own function to do this is thankfully very simple. All that needs to be passed to the function is the string and the tags you want to remove:

strip_only($str, '<br /><hr />');

The function scans all the tags in the string and if found removes them this is all done is a loop then once finished returns the string. 

function strip_only($str, $tags) {

if(!is_array($tags)) {

$tags = (strpos($str, '>') !== false ? explode('>', str_replace('<', '', $tags)) : array($tags));

if(end($tags) == '') array_pop($tags);

}

foreach($tags as $tag) $str = preg_replace('#</?'.$tag.'[^>]*>#is', '', $str);

return $str;

}

 

David Carr

David Carr

For the past 12 years, I’ve been developing applications for the web using mostly PHP. I do this for a living and love what I do as every day there is something new and exciting to learn.

In my spare time, the web development community is a big part of my life. Whether managing online programming groups and blogs or attending a conference, I find keeping involved helps me stay up to date. This is also my chance to give back to the community that helped me get started, a place I am proud to be apart of.

Besides programming I love spending time with friends and family and can often be found together going out catching the latest movie, staying in playing games on the sofa or planning a trip to someplace I’ve never been before.