Check to see if an object is empty (contains no enumerable properties). As of jQuery 1.4 this method checks both properties on the object itself and properties inherited from prototypes (in that it doesn't use hasOwnProperty). The argument should always be a plain JavaScript Object as other types of object (DOM elements, primitive strings/numbers, host objects) may not give consistent results across browsers. To determine if an object is a plain JavaS

Determine whether an element has any jQuery data associated with it. The jQuery.hasData() method provides a way to determine if an element currently has any values that were set using jQuery.data(). If no data is associated with an element (there is no data object at all or the data object is empty), the method returns false; otherwise it returns true. The primary advantage of jQuery.hasData(element) is that it does not create and associate a data obj

Search for a specified value within an array and return its index (or -1 if not found). The $.inArray() method is similar to JavaScript's native .indexOf() method in that it returns -1 when it doesn't find a match. If the first element within the array matches value, $.inArray() returns 0. Because JavaScript treats 0 as loosely equal to false (i.e. 0 == false, but 0 !== false), to check for the presence of value within array, you need to check if it's

Execute some JavaScript code globally. This method behaves differently from using a normal JavaScript eval() in that it's executed within the global context (which is important for loading external scripts dynamically). jQuery.globalEval( code ) version added: 1.0.4 code String

Load data from the server using a HTTP GET request. This is a shorthand Ajax function, which is equivalent to: $.ajax({ url: url, data: data, success: success, dataType: dataType }); The success callback function is passed the returned data, which will be an XML root element, text string, JavaScript file, or JSON object, depending on the MIME type of the response. It is also passed the text status of the response. As of jQuery 1.5, the succes

The rate (in milliseconds) at which animations fire. This property can be manipulated to adjust the number of frames per second at which animations will run. The default is 13 milliseconds. Making this a lower number could make the animations run smoother in faster browsers (such as Chrome) but there may be performance and CPU implications of doing so. Since jQuery uses one global interval, no animation should be running or all animations should stop

Finds the elements of an array which satisfy a filter function. The original array is not affected. The $.grep() method removes items from an array as necessary so that all remaining items pass a provided test. The test is a function that is passed an array item and the index of the item within the array. Only if the test returns true will the item be in the result array. The filter function will be passed two arguments: the current array item and it

A factory function that returns a chainable utility object with methods to register multiple callbacks into callback queues, invoke callback queues, and relay the success or failure state of any synchronous or asynchronous function. The jQuery.Deferred() factory creates a new deferred object. The jQuery.Deferred method can be passed an optional function, which is called just before the method returns and is passed the new deferred object as both the t

Globally disable all animations. When this property is set to true, all animation methods will immediately set elements to their final state when called, rather than displaying an effect. This may be desirable for a couple reasons: jQuery is being used on a low-resource device. Users are encountering accessibility problems with the animations. Animations can be turned back on by setting the property to false. jQ

Merge the contents of two or more objects together into the first object. When two or more object arguments are supplied to $.extend(), properties from all of the objects are added to the target object. Arguments that are null or undefined are ignored. If only one argument is supplied to $.extend(), this means the target argument was omitted. In this case, the jQuery object itself is assumed to be the target. By doing this, you can add new functions t