The td and th objects reflect the td and th elements. From an HTML structure viewpoint, the two elements have different purposes within a table; but from a scripting perspective, the elements share the same properties and methods. A cell is a cell.

Reflects the abbr attribute (cell description for speech), for which mainstream browsers have no functionality at this time.

Defines the horizontal alignment of content within the cell.

Reflects the axis attribute (cell category description for speech), for which mainstream browsers have no functionality at this time.

Specifies the URL of the background image for the cell. If you set a bgColor to the element as well, the color appears if the image fails to load; otherwise, the image overlays the color.

Provides the background color of the table cell. This color setting is not reflected in the style sheet backgroundColor property. Even if the bgcolor attribute or bgColor property is set with a plain-language color name, the returned value is always a hexadecimal triplet.

Removes focus from the current object, at which time the object's onblur event fires. Note that the range of elements capable of focus and blur (both the event and method) is limited in all browsers except for more recent versions of IE (see the shared tabindex attribute in Chapter 8). Most reliably for backward compatibility, apply the blur( ) method to blatantly focusable elements, such as text input and textarea elements. Assigning the attribute onfocus="this.blur( );" to a text input element, for instance, is a crude but effective backward-compatible way to largely disable a field for browsers that do not provide genuine element disabling.

Provides the color of the element's border. Internet Explorer applies the color to all four lines that make up the interior border of a cell. Therefore, colors of adjacent cells do not collide.

The 3-D effect of table borders in Internet Explorer is created by careful positioning of light and dark lines around the page's background or default color. You can independently control the colors used for the dark and light lines by assigning values to the borderColorDark (left and top edges of the cell) and borderColorLight (right and bottom edges) properties.

Returns a zero-based integer representing the position of the current cell among all other td elements in the same row. The count is based on the source code order of the td elements within a tr element. This property is not available in the Macintosh version of Internet Explorer 4.

Defines the text character used as an alignment point for text within a cell. This property is normally of value only for the align attribute set to "char". In practice, neither IE nor Navigator responds to these properties.

Defines the offset point at which the character specified by the char attribute is to appear within a cell. In practice, neither IE nor Navigator responds to these properties.

Broadly speaking, these provide the height and width of the element's content, but with minor variations with respect to element padding among various operating system versions of IE and compatibility modes controlled by the DOCTYPE declaration. Not available for all element types in IE for Macintosh. For Netscape 7, values are zero except when an element's content overflows the viewable area, in which case the values reveal the dimensions of the viewable area (e.g., the browser window's content region for the document.body element). See the Section 9.2 at the beginning of this chapter for details.

Specifies the number of columns across which the current table cell should extend itself. For each additional column included in the colSpan count, one less td element is required for the table row. If you set the align property to center or right, the alignment is calculated on the full width of the td element across the specified number of columns. Unless the current cell also specifies a rowspan attribute, the next table row returns to the original column count.

Returns an array of all filter objects contained by the current element. Applies only to the following element objects: bdo, body, button, div, fieldset, img, input, marquee, rt, ruby, span, table, td, textarea, and th. See the filter object for referencing syntax.

Gives focus from the current object, at which time the object's onfocus event fires. Note that the range of elements capable of focus and blur (both the event and method) is limited in all browsers except for more recent versions of IE (see the shared tabindex attribute in Chapter 8). Most reliably for backward compatibility, apply the focus( ) method to blatantly focusable elements, such as text input and textarea elements.

Points to the ID of a table cell element designated as a column header for the current cell. In practice, no mainstream browsers provide functionality for this property.

Specify the height and width of the element. Changes to these values are immediately reflected in reflowed content on the page. These properties are read-only in the Macintosh version of Internet Explorer 4.

Indicates whether the browser should render the cell as wide as is necessary to display a line of nonbreaking text on one line. Abuse of this attribute can force the user into a great deal of inconvenient horizontal scrolling of the page to view all of the content.

Specifies the number of rows through which the current table cell should extend itself downward. For each additional row included in the rowSpan count, one less td element is required for the next table row. If you set the vAlign property to middle, the alignment is calculated on the full height of the td element across the specified number of rows.

Reflects the scope attribute of table cell elements. In practice, no mainstream browsers provide functionality for this property.

Specifies the manner of vertical alignment of text within the element's content box.

See height.