General

• $(“#id”);
• $(“.class”);
• $(“xpath”);

<script type="text/javascript">
var $j = jQuery.noConflict();

$j(document).ready(function() {
// Code that uses jQuery's $ can follow here like $j("div").hide();
});

// Code that uses other library's $ can follow here.
</script>

• css() can be used to change the style dynamically. Properties as {‘color’:”#000″, ‘display’:”block”};
• addClass(), removeClass() and removeClass() to add, remove or toggle a class.
• animate() gives the properties to which the animation moves. We can use easing function and speed and call back function executed after completion.
• setInterval() and clearInterval() to repeat after an interval and setTimeout() and clearTimeout() to be executed after timeout. There is also delay to bring in a delay between functions.
• slideUp(), slideDown() and slideToggle() and fadeIn(), fadeOut() and fadeToggle().
• clone() will clone a copy which could be used later say for appending.
• html(), text() and empty() and val().
• append(), prepend() — inside block and after(), before() — outside block.
• ajax() will dynamically load contents, scripts and data. load() to grab html from another page given the URL

• $.ajax({
  url: filename,
  type: "GET",
  dataType: "html",
  beforeSend: function () {},
  success: function (data, textStatus, xhr) {},
  error: function (xhr, textStatus, errorThrown) {}
  });

• bind() and unbind() to add an event to an existing code on page load. We can use live() for adding to a dynamically added code also but delegate() preferred. on() and off() is the best method available for same.
• preventDefault() prevents default firing action say href of a link. stopPropogation() stops event firing on ancestors. Events are fired in the order they are bound. stopImmediatePropogation() stops all future bound events.
• each(fn) will execute function on each element of object.
• data() will attach data to any DOM element. removeData() removes key and values. $.hasData inform status.

• jQuery.data(div, "test", { first: 16, last: "pizza!" });
  
  $("span:first").text(jQuery.data(div, "test").first);

• match() extracts part of a string matching a regex whereas test() checks if it matches. contains() checks it in parent and children.
• find(selector) gives descendents matching the selector. filter() is similar but also applies it to the parent.
• slice() can be used to perform actions on a subset of elements prev() and next() on immediate elements in a matched set of array.
• $.extend(target, obj1, obj2, …) combines two or more objects into target object.
• serialize() will create a string from a form and serializeArray() an array from form.