Character Counter in Custom Post Type excerpts

functions.php

function CPT_excerpt_counter(){
	// make sure to change all occurrences of the counter limit.
	if ('YOUR_POST_TYPE' == get_post_type()) {
	
		  echo '<script>jQuery(document).ready(function(){
			jQuery("#postexcerpt .handlediv").after("<div style=\"position:absolute;top:12px;right:34px;color:#666;\"><small>Excerpt length: </small><span id=\"excerpt_counter\"></span><span style=\"font-weight:bold; padding-left:7px;\">/ 100</span><small><span style=\"font-weight:bold; padding-left:7px;\">character(s).</span></small></div>");
		 	jQuery("span#excerpt_counter").text(jQuery("#excerpt").val().length);
		 	jQuery("#excerpt").keyup( function() {
				if(jQuery(this).val().length > 100){
					jQuery(this).val(jQuery(this).val().substr(0, 100));
				}
		 	jQuery("span#excerpt_counter").text(jQuery("#excerpt").val().length);
	   			});
			});</script>';
		}
	}
add_action( 'admin_head-post.php', 'CPT_excerpt_counter');
add_action( 'admin_head-post-new.php', 'CPT_excerpt_counter');