Highlight Search Terms


Highlights search terms within WordPress generated search results or when referrer is a non-secure search engine, both on the search results page and on the post page itself.

This plugin is light weight and has no options. It started as very simple fusion between How to Highlight Search Terms with jQuery – theme hack by Thaya Kareeson and Search Hilite by Ryan Boren. It has since evolved with many optimizations, HTML5 and bbPress support.

Many WordPress sites are already top-heavy with all kinds of resource hungry plugins that require a lot of options to be set and subsequently more database queries. The Highlight Search Terms plugin for WordPress is constructed to be as low impact / low resource demanding as possible, keeping server response and page load times low.
This is done by going without any back-end options page, no filtering of post content and no extra database entries. A limited amount of hooks are used. The rest is done by jQuery javascript extention and your own CSS.


  • Click through highlights: Highlights not only on WP search results page but also one click deeper inside any of the found pages
  • Character and case insensitive (lenient) highlighting
  • BuddyPress / bbPress compatibility: highlighting within forum searches
  • Caching (WP Super Cache) compatibility
  • Search terms wrapped in double quotes now considered as single term

What does it do?

This low impact plugin uses only a few action hooks to define some variables and to add the hilite jQuery extension to your page source code.
The jQuery extension that runs after the page has loaded, finds all search terms on that page inside each div with class hentry (or ID content, main or wrapper…) and wraps them in <mark class="hilite term-N"> ... </mark> tags.
Note that N is a number starting with 0 for the first term used in the search phrase increasing 1 for each additional term used. Any part of a search phrase wrapped in quotes is considered as a single term.

What does it NOT do?

There are no CSS style rules set for highlighting. You are free to use any styling you wish but to make the highlights visible in browsers that do not support HTML5 like Internet Explorer 8 or older you absolutely need to define at least one rule.
Modern HTML5 browsers will use their own highlighting style by default, which usually is a yellow marker style background.

So what do I need to do?

In most cases, it should just work. But you can do two things to ensure backward browser and theme compatibility:

1. Define CSS rules: There are no configuration options and there is no predefined highlight styling. You are completely free to define any CSS styling rules in your themes main stylesheet (style.css) or the Custom CSS tab if the WordPress theme customizer.
You can find basic instructions and CSS examples in the FAQ’s.

2. Check your theme: In most up to date themes (including WP’s own default theme) post and page content is shown inside a div with class hentry. This means search terms found in post and page content will be highlighted but not similar terms that accidentaly show in the page header, sidebar or footer.
If your current theme does not use the hentry class (yet), this plugin will look for IDs content, main and finally wrapper but if none of those are found, it will not work for you out of the box. See the last of the FAQ’s for ways to make it work.

Known issues & development

  1. If your theme does not wrap the main content section of your pages in a div with class «hentry» or HTML5 article tags, this plugin might not work for you out of the box. However, you can make it work. See the last of the FAQ’s for an explanation.

  2. Josh pointed out a conflict with the ShareThis buttons plugin. Since then, that plugin has been completely rewriten so please let me know if the problem still exists. Thanks!

  3. When search engine referrer is using SSL (notice the https:// in the URL) then the search terms cannot be determined. Most search engines are always over SSL nowadays. There is no way to get around that issue.

Please file bug reports and code contributions as pull requests on GitHub.


Συχνές Ερωτήσεις

Installation instructions

To make it work, you will need to take up to three steps, depending on your wishes and WordPress theme. (I) A normal installation and activation procedure; (II) Make sure your theme uses any of the recognized classes or ID’s for the post content div so that the script knows where and where not to look for search terms;
and (III) optionally add CSS styling rules to get highlighting for older browsers that do not support HTML5 like Internet Explorer 8 and below.

I. Install now or use the slick search and install feature (Plugins > Add New and search for «highlight search terms») in your WP2.7+ admin section or follow these basic steps.

  1. Download archive and unpack.
  2. Upload (and overwrite) the /highlight-search-terms/ folder and its content to the /plugins/ folder.
  3. Activate plugin on the Plug-ins page

II. In most up to date themes (including WP’s own Default theme) post and page content is shown inside a div with class hentry.
This class is recognized by the hilite script, which means search terms found in post and page content will be highlighted but not similar terms that coïncidentaly reside in the page header, sidebar or footer.
If your current theme does not use the hentry class (yet), this plugin will look for IDs content, main and finally wrapper (which might include the header, sidebar and footer areas) but if none of those are found, it will not work for you out of the box.
See the last of the FAQ’s for ways to make it work.

III. Optionally add at least one new rule to your themes stylesheet or the Custom CSS editor to style highlightable text.

For example use .hilite { background:#D3E18A; } to get a moss green background on search terms found in the content section (not header, sidebar or footer; assuming your Theme uses a div with class «hentry»).

Please find more examples in the FAQ’s.

I do not see any highlighting!

This plugin has no configuration options page and there is no predefined highlight styling. For any highlighting to become visible in browsers that do not support HTML5 like Internet Explorer 8 or older, you have to complete step III of the installation process.
Edit your themes stylesheet (style.css) or the WordPress theme customizer Custom CSS tab to contain a rule that will give you exactly the styling that fits your theme.

I want to customize the highlighting but have no idea what to put in my stylesheet. Can you give me some examples?

Go in your WP admin section to Appearance > Customize and add one of the examples below to get you started.

For a moss green background highlighting:

.hilite { background-color:#D3E18A }

Yellow background highlighting:

.hilite { background-color:yellow }

A light blue background with bold font:

.hilite { background-color:#9CD4FF; font-weight:bold }

Orange background with black font:

.hilite { background-color:#FFCA61; color:#000000 }
Please give me more advanced CSS examples

If you want to give different terms used in a search phrase a different styling, use the class «term-N» where N is a number starting with 0, increasing 1 with each additional search term, to define your CSS rules.
The below example will make every instance of any term used in the query show up in bold text and a yellow background except for any instance of a second, third and fourth term which will have respectively a light green, light blue and orange background.

.hilite { background-color:yellow; font-weight:bold } /* default */
.term-1 { background-color:#D3E18A } /* second search term only */
.term-2 { background-color:#9CD4FF } /* third search term only */
.term-3 { background-color:#FFCA61 } /* fourth search term only */

Keep in mind that for the first search term the additional class «term-0» is used, not «term-1»!

I really do not see any highlighting!

Due to a problem with jQuery’s $('body') call in combination with many other scripts (like Google Ads, Analytics, Skype Check and other javascript) in the ever increasingly popular Firefox browser, I have had to limit the script search term wrapping to a particular div instead of the whole document body.
I chose div with class «hentry» since that is the most commonly used content layer class in WordPress themes. If that is not available, the script will look for divs #content then #main then #wrapper. However, in your particular theme, none of these divs might be available…

Let’s suppose your theme’s index.php or single.php has no <div <?php post_class() ?> ... > but wraps the post/page content in a <div id="common" class="content"> ... </div>. You can do one of three things to solve this:

A. Change your theme templates like single.php, page.pho and search.php so the post/page content div has a class «hentry» (you can append it to existing classes with a space like class="content hentry").

B. Change the source of wp-content/plugins/highlight-search-terms/hlst.php so that the array starting on line 55 contains your main content ID or class name. In the above example that can be either '#common', or '.content', where a prefix ‘#’ is used for ID and ‘.’ for class.

C. Switch to a theme that does abide by the current WordPress conventions 🙂


Works great!

Very good plugin for expand standard search function. Simple and necessary. Thanks so much.

improved search

Just installed this and it works perfectly out of the box. The default wp search shows the pages on which the searched word appears, but the highlighter shows every instance of it at a glance. Great and easy improvement for search results.

Works great

This plugin works great. Does exactly what it says. Thank you for the CSS examples for highlighting, they were indispensable to me since I'm a newbie. I know this is lightweight and new features would bloat, but if there could be one feature request I think it would be to allow visitors to turn off the highlighting once they are on the page. It can be distracting if they end up just wanting to read. I can see that the extra bit at the end of the URL can just be deleted, but most people would never know to do that. Best to keep it simple, I agree, so good job. Thanks so much for this plugin!

Highlights the Search Results AND the Post page

Finally found a plugin that highlights search text not only on the Search Results page but also highlights the results when you click on a page that has been returned in the search results. Brilliant. I used the following CSS to change the mark color to obtain the color that I desired. /* Highlight Search Terms css */ mark { background-color: #faa460; font-weight: normal; color: black; }

Clashes with Gravity Forms

Edit: Seems to work reasonably now. ---- For some reason the code for this plugin is run in an ajax call for modifying Gravity Forms in the backend. It causes the following error PHP Fatal error: Uncaught Error: Call to a member function get() on null in domain/public_html/wp-includes/query.php:28 Stack trace: #0 domain/wp-content/plugins/bbpress/includes/common/template.php(2036): get_query_var('_bbp_query_name') #1 domain/wp-content/plugins/bbpress/includes/common/template.php(2024): bbp_get_query_name() #2 domain/wp-content/plugins/bbpress/includes/common/template.php(809): bbp_is_query_name('bbp_search') #3 domain/wp-content/plugins/highlight-search-terms/hlst.php(97): bbp_is_search() #4 domain/wp-includes/class-wp-hook.php(298): HighlightSearchTerms::add_url_filters(Object(WP_Query)) #5 domain/wp-includes/class-wp-hook.php(323): WP_Hook->apply_filters(NULL, Array) #6 domain/wp-includes/plugin.php(515): WP_Hook->do_action(Array)
Ανάγνωση όλων των 26 κριτικών

Συνεισφέροντες & Προγραμματιστές

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Σύνοψη αλλαγών


Date 2019-03-07

  • FIX: cyrillic case sensitive results
  • Script compression


Date 2018-03-10

  • Move to wp_add_inline_script


Date 2017-12-22

  • Fix possible vulnerability in append_search_query()
  • Prepare translation text domain


Date 2017-11-23

  • FIX: Prevent bbp_is_search() on admin triggered by Gravity Forms, reported by @dicoeenvoud


Date 2017-02-24

  • FIX: XSS vulnerability reported by Ben Bidner @ Automattic


Date 2017-01-31
Dev time: 3h

  • BUGFIX: [] operator not supported for strings in PHP 7, thanks @seppsoft
  • Drop pre WP 3.7 support
  • Improved bbPress support


Date 2016-10-04
Dev time: 3h

  • BUGFIX: use filtered search terms for click through highlighting


Date 2016-07-20
Dev time: 2h

  • BUGFIX: incompatibility with Relevanssi and other search plugins


Date 2016-04-10
Dev time: 6h

  • Better search results click though highlighting
  • Improved bbPress compatibility
  • Renamed Minified js

Date 2015-10-13
Dev time: 1h

  • FIX: Missing terms not wrapped in P tag (reported by zmokin)


Date 2014-09-04
Dev time: 5h

  • WordPress 3.8 search compatibility allowing less fuzzy search with quotes
  • ?sentence=1 query parameter compat
  • FIX: XSS vulnerability found by Rodolfo Godalle, Jr.


Date 2013-09-02
Dev time: 2h

  • BuddyPress and bbPress highlighting within forum searches
  • FIX: jQuery 1.10 compatibility


Date 2013-07-28
Dev time: 1h

  • FIX: Combine-JS compatibility (Thanks to Joshua Hoke)
  • More possible classes and ids to look for


Date 2012-12-16
Dev time: 1h

  • BUGFIX: non-western languages in URL not decoded


Date 2012-12-06
Dev time: 1h

  • BUGFIX: javascript infinite loop


Date 2012-10-11
Dev time: 6h

  • Search terms wrapped in double quotes now considered as single term
  • Caching compatible
  • Second click highlighting: not only on the search results page but also inside any of the found pages
  • Speed improvement
  • More search engines supported
  • BUGFIX: Undefined variable: cache_compat


Date 2012-07-27
Dev time: 1h

  • BUGFIX: non HTML5 browser (IE8 and older) support failing


Date 2012-07-25
Dev time: 8h

  • NEW: Caching (WP Super Cache) compatibility
  • NEW: Highlights not only on WP search results page but also one click deeper inside any of the found pages
  • NEW: Search terms wrapped in double quotes now considered as single term
  • support many more search engines: AOL, Dogpile, Search.com, Goodsearch.com, Mywebsearch.com, Webcrawler.com, Info.com
  • rebuilt as Class
  • plugin speed improvements


Date 2012-04-18
Dev time: 2h

  • HTML5 mark tag support
  • No more word boundary limit for non-latin based languages compatibility


Date: 2011-01-03
Dev time: 1h

  • BUGFIX: conflict with Cufon script


Date: 2010-09-06
Dev time: 2h

  • limit highlighted search terms to word boundary
  • added Bing, Ask, Baidu and Youdao search engines
  • now automatically check for and highlights in multiple theme div areas
  • BUGFIX: cloning first result excerpt to all excerpts


Date: 2010-08-07
Dev time: 2h

  • using jQuery in no-conflict mode and $hlst instead of $ to avoid conflict with prototype
  • split variables and moved js extension in compacted form to static file
  • moved jQuery and extention to footer + only when actually needed for faster page load


Date: 2010-04-07
Dev time: 1h

  • fixed Regular Expression to allow parts of words to be highlighted
  • search term wrapping limited to .hentry divs


Date: 2009-04-16
Dev time: 1h

  • Bugfix for Firefox 2+ (forcefully highlights now limited to div#content)


Date: 2009-04-15
Dev time: 1h

  • Allowing for multiple search term styling
  • Bugfix for IE7 / IE8, thanks to Jason


Date: 2009-04-14
Dev time: 3h

  • Basic plugin aimed at low impact / low resource demand on your WP installation using client side javascript.