function isValidDate(value, userFormat) {

 // Set default format if format is not provided
 userFormat = userFormat || 'mm/dd/yyyy';

 // Find custom delimiter by excluding
 // month, day and year characters
 var delimiter = /[^mdy]/.exec(userFormat)[0];

 // Create an array with month, day and year
 // so we know the format order by index
 var theFormat = userFormat.split(delimiter);

 // Create array from user date
 var theDate = value.split(delimiter);

 function isDate(date, format) {
  var m, d, y, i = 0, len = format.length, f;
  for (i; i < len; i++) {
   f = format[i];
   if (/m/.test(f)) m = date[i];
   if (/d/.test(f)) d = date[i];
   if (/y/.test(f)) y = date[i];
  }
  return (
   m > 0 && m < 13 &&
   y && y.length === 4 &&
   d > 0 &&
   // Check if it's a valid day of the month
   d <= (new Date(y, m, 0)).getDate()
  );
 }

 return isDate(theDate, theFormat);
}

var getMaxHeight = function ($elms) {
 var maxHeight = 0;
 $elms.each(function () {
  // In some cases you may want to use outerHeight() instead
  var height = $(this).height();
  if (height > maxHeight) {
   maxHeight = height;
  }
 });
 return maxHeight;
};

function highlight(text, words, tag) {

 // Default tag if no tag is provided
 tag = tag || 'span';

 var i, len = words.length, re;
 for (i = 0; i < len; i++) {
  // Global regex to highlight all matches
  re = new RegExp(words[i], 'g');
  if (re.test(text)) {
   text = text.replace(re, '<'+ tag +' class="highlight">$&</'+ tag +'>');
  }
 }

 return text;
}

function unhighlight(text, tag) {
 // Default tag if no tag is provided
 tag = tag || 'span';
 var re = new RegExp('(<'+ tag +'.+?>|<\/'+ tag +'>)', 'g');
 return text.replace(re, '');
}

$('p').html( highlight(
  $('p').html(), // the text
  ['foo', 'bar', 'baz', 'hello world'], // list of words or phrases to highlight
  'strong' // custom tag
));

$.fn.animateText = function(delay, klass) {

 var text = this.text();
 var letters = text.split('');

 return this.each(function(){
  var $this = $(this);
  $this.html(text.replace(/./g, '<span class="letter">$&</span>'));
  $this.find('span.letter').each(function(i, el){
   setTimeout(function(){ $(el).addClass(klass); }, delay * i);
  });
 });

};

$.fn.fadeAll = function (ops) {
 var o = $.extend({
  delay: 500, // delay between elements
  speed: 500, // animation speed
  ease: 'swing' // other require easing plugin
 }, ops);
 var $el = this;
 for (var i=0, d=0, l=$el.length; i<l; i++, d+=o.delay) {
  $el.eq(i).delay(d).fadeIn(o.speed, o.ease);
 }
 return $el;
}