A PHP function that generates a Code 39 type barcode in pure HTML/CSS

generate_code39_barcode.php

// Prints out a Code 39 barcode in HTML/CSS
// $string should be a Code 39-compliant string to encode.
// Any characters not in the array below will be discarded.
function print_code39_barcode($string) {
	$code39 = array(
		'0'=>'NnNwWnWnN',	'1'=>'WnNwNnNnW',
		'2'=>'NnWwNnNnW',	'3'=>'WnWwNnNnN',
		'4'=>'NnNwWnNnW',	'5'=>'WnNwWnNnN',
		'6'=>'NnWwWnNnN',	'7'=>'NnNwNnWnW',
		'8'=>'WnNwNnWnN',	'9'=>'NnWwNnWnN',
		'A'=>'WnNnNwNnW',	'B'=>'NnWnNwNnW',
		'C'=>'WnWnNwNnN',	'D'=>'NnNnWwNnW',
		'E'=>'WnNnWwNnN',	'F'=>'NnWnWwNnN',
		'G'=>'NnNnNwWnW',	'H'=>'WnNnNwWnN',
		'I'=>'NnWnNwWnN',	'J'=>'NnNnWwWnN',
		'K'=>'WnNnNnNwW',	'L'=>'NnWnNnNwW',
		'M'=>'WnWnNnNwN',	'N'=>'NnNnWnNwW',
		'O'=>'WnNnWnNwN',	'P'=>'NnWnWnNwN',
		'Q'=>'NnNnNnWwW',	'R'=>'WnNnNnWwN',
		'S'=>'NnWnNnWwN',	'T'=>'NnNnWnWwN',
		'U'=>'WwNnNnNnW',	'V'=>'NwWnNnNnW',
		'W'=>'WwWnNnNnN',	'X'=>'NwNnWnNnW',
		'Y'=>'WwNnWnNnN',	'Z'=>'NwWnWnNnN',
		'-'=>'NwNnNnWnW',	'.'=>'WwNnNnWnN',
		' '=>'NwWnNnWnN',	'$'=>'NwNwNwNnN',
		'/'=>'NwNwNnNwN',	'+'=>'NwNnNwNwN',
		'%'=>'NnNwNwNwN',	'*'=>'NwNnWnWnN');
	
	echo "<style type='text/css'>div.barcode{height:40px;margin:0 auto;padding:0;}div.barcode .black{background-color:black;}div.barcode .white{background-color:white;}div.barcode .narrow{width:1px;}div.barcode .wide{width:3px;}div.barcode div{height:100%;float:left;margin:0;padding:0;}</style>\n";
	echo "<div class='barcode'>";

	// Split the string up into its separate characters and iterate over them
	if (substr($string,0,1)!='*') $string = "*$string";
	if (substr($string,-1,1)!='*') $string = "$string*";
	$string = strtoupper($string);
	$chars = preg_split('//', $string, -1, PREG_SPLIT_NO_EMPTY);
	foreach ($chars as $char) {
		
		// Split this character's encoding string up into its separate characters and iterate
		$pattern = preg_split('//', $code39[$char], -1, PREG_SPLIT_NO_EMPTY);
		foreach ($pattern as $bar) {
			
			// Determine bar's class
			switch ($bar) {
				case 'W': $classes = "wide black"; break;
				case 'N': $classes = "narrow black"; break;
				case 'w': $classes = "wide white"; break;
				case 'n': $classes = "narrow white"; break;
			}
			// Print bar
			echo "<div class='$classes'></div>";
		}
		// Separator between characters
		echo "<div class='narrow white'></div>";
	}
	echo "</div>\n";
}