Quick jQuery plugin to count the number of words in an input/textarea.

jquery.wordcount.js

;(function($) {
  var NONBLANK = /\S/
  var SPLITTER = /[^a-z0-9-]+/i

  function countWords(string) {
    var trimmed = string.replace(/^\s+|\s+$/g, "")

    if (NONBLANK.test(trimmed)) {
      return trimmed.split(SPLITTER).length
    } else {
      return 0
    }
  }

  $.fn.wordcount = function(callback) {
    return this.each(function() {
      var input = $(this)

      input.on("keyup", function() {
        callback.call(this, countWords(input.val()))
      })

      callback.call(this, countWords(input.val()))
    })
  }
})(jQuery);