Tutorial Highlight a Substring

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<?php
       $text='Would you be so kind to highlight css-tricks.com in this string?';
       $search='css-tricks.com';

       echo textHighlight($text,$search);

       //Performs a regex-texthighlight
       function textHighlight($text,$search,$highlightColor='#0000FF',$casesensitive=false)
       {
               $modifier=($casesensitive) ? 'i' : '';
               //quote search-string, cause preg_replace wouldn't work correctly if chars like $?. were in search-string
               $quotedSearch=preg_quote($search,'/');
               //generate regex-search-pattern
               $checkPattern='/'.$quotedSearch.'/'.$modifier;
               //generate regex-replace-pattern
               $strReplacement='$0';
               return preg_replace($checkPattern,$strReplacement,$text);
       }
?>

This code performs a regular-expression-replace to add a span-tag with a definable color. Can be used either for case-sensitive and case-insensitive replacements.

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