Display header text in Theme Customizer

I want to add a javascript function that will show/hide the blog title and description without needing to refresh page when checking/unchecking the “Display header text” checkbox in Theme Customizer. I understand that I need to change the transport attribute to ‘postMessage’ for the setting to this default control. But when looking in class-wp-customize-manager.php the setting that is connected to this control is ‘header_textcolor’. Does anyone know why? And how can I solve this? I need to be able to get the setting of this control, if it is checked or unchecked.