Function: isNode(objectToTest, windowObject, documentObject, numberNodeType1, numberNodeType2, etc.)

Description: Checks if the specified object is a valid DOM node or document object.

Returns: True if yes, False otherwise.

Note: The basic usage where only the first parameter is populated, will check if the specified object is a standard DOM node (instanceof Element). If window is passed as the second parameter, it will check if the object is either a standard DOM node or a window object. If window.document is passed as the third parameter, it will check for that document object type as well. The fourth parameter can be used to specify a specific nodeType value to check for as well, such as 11 to return true if a document fragment is detected. Any number of nodeType values can be checked for as well by adding these as additional parameters after the fourth parameter. The only required parameter is the first one, however.

Example:

// Check if the specified object is a standard DOM node (instanceof Element).
var confirm = $A.isNode(objectToTest);

// Check if the specified object is either a standard DOM node or a document fragment object.
var confirm = $A.isNode(objectToTest, null, null, 11);

// Check if the specified object is a standard DOM node, a document object, or a document fragment object.
var confirm = $A.isNode(objectToTest, null, document, 11);

// Check if the specified object is a standard DOM node, a document object, a document fragment object, or a text node object.
var confirm = $A.isNode(objectToTest, null, document, 11, 3);

// Check if the specified object is a standard DOM node, a window object, or a document object.
var confirm = $A.isNode(objectToTest, window, document);