Highlight Keyword in Content [ERROR w/preg_replace()]

webdes03

I've made a simple search script which returns matching rows from the database where the content contains the searched keyword(s). I want to take it a step further and highlight the keywords when the content is displayed. I created a "highlight" class that changes the background color to make the word(s) stand out, but my stript is giving me an error.

$in = preg_replace($ckeyword, "<span class='highlight'>".$ckeyword."</span>", $in);

I get the error: "Warning, Empty regular expression"

Any ideas what i'm doing wrong?

The $in variable has already been formatted from the raw database data to remove additional whitespace, and convert addresses to links.

laserlight

You would be better off not using regex:

$in = str_replace($ckeyword, "<span class='highlight'>".$ckeyword."</span>", $in);

Still, is $ckeyword an array of regex patterns?
You have to make sure that each of them is delimited by some character (e.g. /), as Perl compatible regex requires that.

webdes03

$ckeyword is a simple variable, such as "car", "house", "orange" whatever you want it to be.

I changed it to:

$in = str_replace($ckeyword, "<span class='highlight'>".$ckeyword."</span>", $in);

The error went away, but it still doesn't work, haha. Any ideas?

Also, I'd like it to be case insensitive if possible, since the search is case insensitive.

laserlight

Let's test:

$in = str_replace($ckeyword, "THE KEYWORD: '" . $ckeyword . "'!!!", $in);

webdes03

My bad, I was calling it in the wrong place... it does work... is there a way to make it case insensitive though?

So "car" and "Car" would both highlight?

laserlight

nope.
In that case, you should use regex.

$in = preg_replace('/' . $ckeyword . '/i', "<span class='highlight'>".$ckeyword."</span>", $in);

webdes03

Thanks for all your help so far, I can't figure out how to make that caseinsensitive though...

laserlight

My regex example is case-insensitive.

Basically,
/pattern/i
matches "pattern" without regard to upper/lower case.

webdes03

Ahhhh... I'm sorry, I left off the 'i'. Thanks for all your help.