倒计时;不起作用

我是JavaScript的初学者。我想做一个真正的极简倒计时，我发现了这个脚本：http://codepen.io/scottobrien/pen/Fvawk

但当我尝试用我的设置自定义它时，什么也没发生。

谢谢你的帮助。

这是我的代码

<ul class="countdown">
  <li>
    <span class="days"></span>
    <p class="timeRefDays"></p>
  </li>
  <li>
    <span class="hours"></span>
    <p class="timeRefHours"></p>
  </li>
  <li>
    <span class="minutes"></span>
    <p class="timeRefMinutes"></p>
  </li>
  <li>
    <span class="seconds"></span>
    <p class="timeRefSeconds"></p>
  </li>
</ul>
(function($) {
$.fn.countdown = function(options, callback) {
  //custom 'this' selector
  var thisEl = $(this);
  //array of custom settings
  var settings = { 
    'date': 7 May 2012 17:30:00;
    'format': on
  };
  //append the settings array to options
  if(options) {
    $.extend(settings, options);
  }
  //main countdown function

    function countdown_proc() {
        var eventDate = Date.parse(settings['date']) / 1000;
        var currentDate = Math.floor($.now() / 1000);
        if(eventDate <= currentDate) {
          callback.call(this);
          clearInterval(interval);
        }
        var seconds = eventDate - currentDate;
        var days = Math.floor(seconds / (60 * 60 * 24)); //calculate the number of days
        seconds -= days * 60 * 60 * 24; //update the seconds variable with no. of days removed
        var hours = Math.floor(seconds / (60 * 60));
        seconds -= hours * 60 * 60; //update the seconds variable with no. of hours removed
        var minutes = Math.floor(seconds / 60);
        seconds -= minutes * 60; //update the seconds variable with no. of minutes removed
        //conditional Ss
        if (days == 1) { thisEl.find(".timeRefDays").text(""); } else { thisEl.find(".timeRefDays").text(""); }
        if (hours == 1) { thisEl.find(".timeRefHours").text(""); } else { thisEl.find(".timeRefHours").text(""); }
        if (minutes == 1) { thisEl.find(".timeRefMinutes").text("Minute"); } else { thisEl.find(".timeRefMinutes").text("Minutes"); }
        if (seconds == 1) { thisEl.find(".timeRefSeconds").text("Second"); } else { thisEl.find(".timeRefSeconds").text("Seconds"); }
        //logic for the two_digits ON setting
        if(settings['format'] == "on") {
          days = (String(days).length >= 2) ? days : "0" + days;
          hours = (String(hours).length >= 2) ? hours : "0" + hours;
          minutes = (String(minutes).length >= 2) ? minutes : "0" + minutes;
          seconds = (String(seconds).length >= 2) ? seconds : "0" + seconds;
        }
        //update the countdown's html values.
        if(!isNaN(eventDate)) {
          thisEl.find(".days").text(days);
          thisEl.find(".hours").text(hours);
          thisEl.find(".minutes").text(minutes);
          thisEl.find(".seconds").text(seconds);
        } else { 
          alert("Invalid date. Here's an example: 12 Tuesday 2012 17:30:00");
          clearInterval(interval); 
        }
      }
      //run the function
      countdown_proc();
      //loop the function
      interval = setInterval(countdown_proc, 1000);
    }
}) (jQuery);

//Call countdown plugin
$(".countdown").countdown({
  date: "7 May 2014 6:19:00", // add the countdown's end date (i.e. 3 november 2012 12:00:00)
  format: "on" // on (03:07:52) | off (3:7:52) - two_digits set to ON maintains layout consistency
},
function() {
  // the code here will run when the countdown ends
  alert("done!")
});