Scripts and Elements

Scripts and Elements

This chapter shows you how to program and manipulate the elements of an HTML document. All elements share a common set of information for identifying the element, accessing the attributes on the element, and defining the relationships between the element and other elements in the document.

In addition, many elements provide custom properties, methods, and events, giving you increased control of your documents. A sampling of these elements is discussed in Chapter 9, "Scripting Individual Elements," and in Chapter 10, "Forms and Intrinsic Controls." The following topics are covered in this chapter:

• Identifying elements This section shows you how to distinguish between the different elements in the document. HTML exposes a set of attributes that are useful for identifying and grouping elements, including the tag name itself and the ID, CLASS, and NAME attributes.

• Accessing an element's attributes All element objects encapsulate information about their attributes and even provide access to invalid attributes and values that may be specified on an element. This section shows you how to access and use this information.

• Parsing information Chapter 7, "Document Element Collections," described how the document's all collection is constructed and accessed. The all collection provides access to the individual elements, and each element exposes its relationships with other elements, including information about the parsing and rendering of the document. The parsing information represents the underlying HTML source, and the rendering information represents calculated information determined during the creation of the document. This section reviews the relationships between elements in the parsing tree and shows how these relationships are exposed by the individual elements.

• Creating new elements This section shows how elements can be added to the document using the createElement method. There are two techniques for controlling the document's structure: creating elements in memory, and modifying the HTML contents directly. Dynamic HTML currently supports the creation of elements in memory for only a few elements.

• Customizing elements This section demonstrates techniques for customizing existing elements and for creating new user-defined elements. Customization is similar to subclassing an element and takes advantage of Dynamic HTML's ability to expose unrecognized attributes to the scripting language. Custom elements can also be defined by accessing and using unrecognized elements in the object model. These user-defined elements can contain extra meta information about the document that can be accessed and manipulated through the object model.

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