How Objects are Organized in a Web Document

The Objects are organized in a hierarchy. This hierarchical structure applies to the organization of objects in a Web document.

• Window object − Top of the hierarchy. It is the utmost element of the object hierarchy.
• Document object − Each HTML document that gets loaded into a window becomes a document object. The document contains the contents of the page.
• Form object − Everything enclosed in the <form>...</form> tags sets the form object.
• Form control elements − The form object contains all the elements defined for that object such as text fields, buttons, radio buttons, and checkboxes.

The following is a simple hierarchy of a few important objects −