<a href="mailto:infoATpareto-interimPUNKTcom" onclick="this.href=this.href.replace(/AT/,'&#64;').replace(/PUNKT/,'&#46;')">
    info<span>extra</span>@pareto<span>content</span>-interim.com
</a>


$("a.ehandler").on('click', function() {
    this.href = this.href.replace(/kontakt./,'');
});


// Hide email from Spam Bots in shortcode.
function wpcodex_hide_email_shortcode( $atts , $content = null ) {
    if ( ! is_email( $content ) ) {
        return;
    }
    return '<a class="ehandler" href="mailto:kontakt.' . $content . '"><span>kontakt.</span>' . $content . '</a>';
}
add_shortcode( 'email', 'wpcodex_hide_email_shortcode' );