Custom HTML WordPress Shortcode - add any HTML tag in the WYSIWYG editor!

html-markup-shortcodes.php

/**
 * HTML MARKUP SHORTCODES
 * by Nick Bair
 * 
 * This is a nice little cheater shortcode for devs who don't want the WordPress
 * WYSIWYG editor to strip out their HTML tags.
 * 
 * 
 * 
 * USAGE
 * 
 * Any HTML tag can be produced with a shortcode like so:
 * 
 *   [markup tag="abbr"]NASA[/markup]
 * 
 * You can include any HTML attribute:
 * 
 *   [markup tag="abbr" title="Not A Space Acronym"]NASA[/markup]
 * 
 * 
 * 
 * NESTING
 * 
 * You can nest shortcodes, but you can't nest shortcodes with the same name.
 * To allow for nesting, we've included some special-case shortcodes which you
 * can use:
 * 
 *   [markup-a tag="blockquote"]
 *     Don't believe everything you read on the Internet.
 *     [markup-b tag="cite"]Abraham Lincoln[/markup-b]
 *   [/markup-a]
 * 
 * We've set up letters A-D for this purpose. Honestly, if that's not enough
 * nesting for you, why aren't you coding it into your template?
 * 
 * 
 * 
 * SHORTCUTS
 * 
 * We've included some shortcut codes to help with some commonly-used tags.
 * They are as follows:
 * 
 * - [div]
 * - [span]
 * - [link] (produces <a> tags)
 * - [img]
 * 
 * 
 * 
 * CUSTOMIZING
 * 
 * You can add more shortcuts if you want by copying & pasting the
 * add_shortcode() functions below and changing the first argument.
 * 
 */
function html_markup_shortcode($atts, $content = null, $tag) {
    switch ($tag) {
        case 'markup':
        case 'markup-a':
        case 'markup-b':
        case 'markup-c':
        case 'markup-d':
        case 'div':
        case 'div-a':
        case 'div-b':
        case 'div-c':
        case 'div-d':
            $markup_tag = (isset($atts['tag'])) ? $atts['tag'] : 'div';
            break;
        case 'link':
            $markup_tag = 'a';
            break;
        default:
            $markup_tag = $tag;
    }
    
    unset ($atts['tag']);
    
    $attributes = '';
    
    foreach ($atts as $k => $v) {
        $attributes .= " ${k}=\"${v}\"";
    }
    
    $output = "<${markup_tag}${attributes}>";
    $output .= ( ! is_null($content)) ? do_shortcode($content) : '';
    $output .= "</${markup_tag}>";
    
    return $output;
}
add_shortcode( 'markup',   'html_markup_shortcode' );
add_shortcode( 'markup-a', 'html_markup_shortcode' );
add_shortcode( 'markup-b', 'html_markup_shortcode' );
add_shortcode( 'markup-c', 'html_markup_shortcode' );
add_shortcode( 'markup-d', 'html_markup_shortcode' );
add_shortcode( 'div',      'html_markup_shortcode' );
add_shortcode( 'div-a',    'html_markup_shortcode' );
add_shortcode( 'div-b',    'html_markup_shortcode' );
add_shortcode( 'div-c',    'html_markup_shortcode' );
add_shortcode( 'div-d',    'html_markup_shortcode' );
add_shortcode( 'span',     'html_markup_shortcode' );
add_shortcode( 'link',     'html_markup_shortcode' );
add_shortcode( 'img',      'html_markup_shortcode' );