jQuery implements a method to limit the number of characters entered into a textarea text box_jquery

(function($) {
  $.fn.extend( {
    limiter: function(limit, elem) {
      $(this).on("keyup focus", function() {
        setCount(this, elem);
      });
      function setCount(src, elem) {
        var chars = src.value.length;
        if (chars > limit) {
          src.value = src.value.substr(0, limit);
          chars = limit;
        }
        elem.html( limit - chars );
      }
      setCount($(this)[0], elem);
    }
  });
})(jQuery);
 
//To setup the limiter, simply include a call similar to the one below:
var elem = $("#chars");
$("#text").limiter(100, elem);