WordPress: Comment Length Limiter

limit.js

jQuery(function($) {
	// configure
	var comment_input = $( '#commentform textarea' );
	var submit_button = $( '#commentform .form-submit' );
	var comment_limit_chars = 1000;
	// stop editing here
	
	// display how many characters are left
	$( '<div class="comment_limit_info"><span>' + comment_limit_chars + '</span> characters left</div>' ).insertAfter( comment_input );
	
	comment_input.bind( 'keyup', function() {
		// calculate characters left
		var comment_length = $(this).val().length;
		var chars_left = comment_limit_chars - comment_length;
		
		// display characters left
		$( '.comment_limit_info span' ).html( chars_left );
		
		// hide submit button if too many chars were used
		if (submit_button)
			( chars_left < 0 ) ? submit_button.hide() : submit_button.show();
	});
});