Snippet to count how many characters are left in a textarea. I use it in the backend of a CMS to insert meta information for social shares (e.g. re-tweets).

charcounter.js

// in HTML: 
// <div id="count"></div>
// <textarea id="#share-description"></textarea>

$(document).ready(function() {
  
var chars = 115; // 140 minus 25 (Twitter links (24 chars) plus 1 whitespace)
var left;
	if ($("#share-description").val().length === 0) {
		left = chars;
	} else {
		left = chars - $("#share-description").val().length;
	}
	$("#count").append("Characters left: " + left);
	$("#share-description").keyup(function () {
	if ($(this).val().length > chars) {
		$(this).val($(this).val().substr(0, chars));
	}
	var left = chars - $(this).val().length;
	$("#count").html("Characters left: " + left);
	if (left <= 12) {
		$("#count").css("color", "#c00");
	} else {
		$("#count").css("color", "#000");
	}
	
});