Convert a String to Title Case (also known as Headline Style or Up Style) Take a string, capitalize the first and last words of the title and all nouns, pronouns, adjectives, verbs, adverbs, and subordinating conjunctions (if, because, as, that, and so on) for example: "Rules for Capitalizing the Words in a Title."

headline_style.php

// Converts a string to Title Case based on one set of title case rules
// Put <no_parse></no_parse> around content that you don't want to be parsed by the title case rules

// Test the function :

// echo titleCase("this is a test <no_parse>do you not believe me</no_parse> here is the rest of the string");

// Which would yield the following output : 
// This Is A Test do you not believe me Here Is The Rest of The String

function titleCase($string) {

	//remove no_parse content
	$string_array = preg_split("/(<no_parse>|<\\/no_parse>)+/i",$string);
	$newString = "";

	for ($k=0; $k< count($string_array); $k=$k+2){
		$string = $string_array[$k];

		//if the entire string is upper case dont perform any title case on it
		if ($string != strtoupper($string)){

			//TITLE CASE RULES:
			//1.) uppercase the first char in every word
			$new = preg_replace("/(^|\\s|\\''|''|\\"|-){1}([a-z]){1}/ie","''''.stripslashes(''\\\\1'').''''.stripslashes(strtoupper(''\\\\2'')).''''", $string);

			//2.) lower case words exempt from title case

			// Lowercase all articles, coordinate conjunctions ("and", "or", "nor"), and prepositions regardless of length, when they are other than the first or last word.

			// Lowercase the "to" in an infinitive." - this rule is of course aproximated since it is contex sensitive

			$matches = array();

			// perform recusive matching on the following words

			preg_match_all("/(\\sof|\\sa|\\san|\\sthe|\\sbut|\\sor|\\snot|\\syet|\\sat|\\son|\\sin|\\sover|\\sabove|\\sunder|\\sbelow|\\sbehind|\\snext\\sto|\\sbeside|\\sby|\\samoung|\\sbetween|\\sby|\\still|\\ssince|\\sdurring|\\sfor|\\sthroughout|\\sto|\\sand){2}/i",$new ,$matches);

			for ($i=0; $i< count($matches); $i++){

				for ($j=0; $j< count($matches[$i]); $j++){

					$new = preg_replace("/(".$matches[$i][$j]."\\s)/ise","''''.strtolower(''\\\\1'').''''",$new);

				}

			}

			//3.) fix capitilized letters after apostrophes

			$new = preg_replace("/(\\w''S)/ie","''''.strtolower(''\\\\1'').''''",$new);

			$new = preg_replace("/(\\w''\\w)/ie","''''.strtolower(''\\\\1'').''''",$new);

			$new = preg_replace("/(\\W)(of|a|an|the|but|or|not|yet|at|on|in|over|above|under|below|behind|next to| beside|by|amoung|between|by|till|since|durring|for|throughout|to|and)(\\W)/ise","''\\\\1''.strtolower(''\\\\2'').''\\\\3''",$new);

			//4.) capitalize first letter in the string always

			$new = preg_replace("/(^[a-z]){1}/ie","''''.strtoupper(''\\\\1'').''''", $new);

			//5.) replace special cases

			// you will add to this as you find case specific problems

			$new = preg_replace("/\\sin-/i"," In-",$new);

			$new = preg_replace("/(\\s|\\"|\\''){1}(ph){1}(\\s|,|\\.|\\"|\\''|:|!|\\?|\\*|$){1}/ie","''\\\\1pH\\\\3''",$new);

			$new = preg_replace("/^ph(\\s|$)/i","pH ",$new);

			$new = preg_replace("/(\\s)ph($)/i"," pH",$new);

			$new = preg_replace("/(\\s|\\"|\\''){1}(&amp;){1}(\\s|,|\\.|\\"|\\''|:|!|\\?|\\*){1}/ie","''\\\\1and\\\\3''",$new);

			$new = preg_replace("/(\\s|\\"|\\''){1}(groundwater){1}(\\s|,|\\.|\\"|\\''|:|!|\\?|\\*){1}/e","''\\\\1Ground Water\\\\3''",$new);
			
			//Standardize words that should be hyphenated. 
			//Example: cross connection => cross-connection
			//$new = preg_replace("/(\\W|^){1}(cross){1}(\\s){1}(connection){1}(\\W|$){1}/ie","''\\\\1\\\\2-\\\\4\\\\5''",$new);

			$new = preg_replace("/(\\s|\\"|\\''){1}(vs\\.){1}(\\s|,|\\.|\\"|\\''|:|!|\\?|\\*){1}/ie","''\\\\1Vs.\\\\3''",$new);

			$new = preg_replace("/(\\s|\\"|\\''){1}(on-off){1}(\\s|,|\\.|\\"|\\''|:|!|\\?|\\*){1}/ie","''\\\\1On-Off\\\\3''",$new);

			$new = preg_replace("/(\\s|\\"|\\''){1}(on-site){1}(\\s|,|\\.|\\"|\\''|:|!|\\?|\\*){1}/ie","''\\\\1On-Site\\\\3''",$new);

			// special cases like Class A Fires or Class C Regulations

			$new = preg_replace("/(\\s|\\"|\\''){1}(class\\s){1}(\\w){1}(\\s|,|\\.|\\"|\\''|:|!|\\?|\\*|$){1}/ie","''\\\\1\\\\2''.strtoupper(''\\\\3'').''\\\\4''",$new);

			$new = stripslashes($new);

			$string_array[$k] = $new;

		} 

	}

	for ($k=0; $k< count($string_array); $k++){

		$newString .= $string_array[$k];

	}

	return($newString); 

};