$.extend(Object)

$.extend(Object prop) returns Object
Extends the jQuery object itself. Can be used to add functions into the jQuery namespace and to [[Plugins/Authoring|add plugin methods]] (plugins).
Example:
Adds two plugin methods.

jQuery.fn.extend({
check: function() {
return this.each(function() { this.checked = true; });
},
uncheck: function() {
return this.each(function() { this.checked = false; });
}
});
$("input[@type=checkbox]").check();
$("input[@type=radio]").uncheck();