Trello show days left Greasemonkey script

trello_days_left.js

// ==UserScript==
// @name        Trello days left
// @namespace   edu.rit.ashbrook.daniel
// @include     https://trello.com/*
// @version     1.1
// @require  http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js
// @require  https://gist.github.com/raw/2625891/waitForKeyElements.js
// @grant    GM_addStyle
// @description Add the number of days left until an item is due to each applicable card.
// ==/UserScript==

var showDaysLeft = function()
{
  $("div.is-due-future.badge span.badge-icon.icon-clock")
    .siblings("span.badge-text")
    .each(
      function()
      {
        var curText = $(this).text();
        if($(this).siblings('.daysLeft').length == 0)  //Don't add extra days left
        {
          var dueDate;
          if(curText.indexOf(",") != -1)   //There's a year, so don't add it
            dueDate = Date.parse(curText);
          else
            dueDate = Date.parse(curText + ", " + (new Date()).getFullYear());
          var daysLeft = Math.floor((dueDate - Date.now())/(3600*24*1000)) + 1;
          $(this).after("<span class='daysLeft' style='color:red; font-weight:bold'> [" + daysLeft + "]</span>");
        }
      }
    )
}

//Run every 1.5s to overcome Trello's Ajax auto-refresh
$(document).ready(function(){setInterval(showDaysLeft, 1500)});