WordPress already has a search system your visitors can use to find content you have created in the past. It is not perfect but does work. There are many ways to enhance it, though. We have already covered a few plugins that take WordPress’ search system to the next level. These 5 search plugins allow you to highlight search results for your visitors:
Relevanssi: replaces the default search with a partial match search and sorts results by relevance. It highlights search terms on your site. Your visitors can search comments, tags, categories, and custom fields.
Highlight Search Terms: find Relevanssi too heavy for your site? This plugin is a more lightweight solution that highlights search terms using jQuery. It is compatible with BuddyPress / bbPress.
Search Everything: enhances WordPress’s default search in various ways. It lets your visitors search pages, tags, categories, and comments. Search highlighting is provided too.
WP Ultimate Search: searches post title and body content. Allows searching by multiple keywords. It highlights search terms in the results pages. It is Google Analytics friendly.
yolink Search: not only enhances your site search but might keep people on your site longer. It also makes your site social friendly.
There are other plugins that get the same job done. You could also write your own code (which is probably the best way to do it if you just need search highlighting). The above plugins do save you some time though.