Objects Objects can contain objects. For example, your document can have a form in it. This form is a 'child object' of the document. Therefore the document is the 'parent object' of the form. To reference the child object, we have to go through the parent object, eg. document.myForm
W3C DOM Specification The objective for the Document Object Model is to provide a standard programming interface that can be used in a wide variety of environments and applications. The DOM is designed to be used with any programming language.
Object Properties Objects have properties, which you can think of as characteristics of an object. Eg href (url string in the browser that determines the page your browser loads) bgColor (background color of the document) value (the text - or lack thereof - in a form text field) src (path and filename of an image)
Object methods Methods are actions that can be applied directly to objects. alert() causes an alert dialog box to appear over the page that launched it (window). write() writes content to a page (document). focus() causes the mouse cursor to be inserted into a form element (text field on form).
Methods And The Dot Syntax Methods are also physically attached to their objects via the dot syntax. To use a method of an object you must first include the complete path to the object (separated by dots of course) the a dot prior to the method. Eg document.formName.TextFieldName.focus() focus() is a method
Functions A function contains code that will be executed by an event or by a call to the function. You may call a function from anywhere within a page (or even from other pages if the function is embedded in an external.js file). Functions can be defined both in the and in the section of a document. However, to assure that a function is read/loaded by the browser before it is called, it could be wise to put functions in the section.