The legend object reflects the legend element. A legend element must be nested inside and immediately after the fieldset element associated with a form or group of form controls.

This is single character key that either gives focus to an element (in some browsers) or activates a form control or link action. The browser and operating system determine if the user must press a modifier key (e.g., Ctrl, Alt, or Command) with the access key to activate the link. In Windows versions of IE 5 and later and Netscape 6, the Alt key is required and the key is not case-sensitive. For Macintosh versions of IE 5 and later and Netscape 6, the Ctrl modifier key is required to effect the action.

Controls the alignment of the legend element with respect to the containing fieldset element. The permissible values do not always work as planned in Internet Explorer 4. Be sure to check your desired setting on all operating system platforms of your intended audience.

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.

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.

Broadly speaking, these provide the left and top coordinates of the element's content within the box that includes the element's padding, but with minor variations among various operating system versions of IE. Not available for all element types in IE for Macintosh. See the Section 9.2 at the beginning of this chapter for details. More useful information for inline element positioning generally comes from the offsetLeft and offsetTop properties (including Netscape 6). For CSS-positioned elements (including changing an element's position), use style object properties, such as left and top, and (in IE only) pixelLeft and pixelTop.

Returns a reference to the next outermost form element object in the document tree. Multiple legend element objects within the same form element reference the same form element object.

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.

Originally implemented in IE 4 for elements that either scrolled or influenced an element's scroll (body, button, caption, div, fieldset, legend, marquee, and textarea), these properties return the pixel dimensions of an element, including elements that are larger than the viewable area in the browser window. This is in contrast to the clientHeight and clientWidth properties for scrollable elements, which return dimensions of only visible portions of the element. IE for the Macintosh, however, interprets the intent of the scroll- properties differently, returning the dimensions of the visible portion.

Provide the distance in pixels between the actual left or top edge of the element's physical content and the left or top edge of the visible portion of the content. Setting these properties allows you to use a script to adjust the scrolling of content within a scrollable container, such as text in a textarea element or an entire document in the browser window or frame. When the content is not scrolled, both values are zero. Setting the scrollTop property to 15 scrolls the document upward by 15 pixels in the window; the scrollLeft property is unaffected unless explicitly changed. The property values change as the user adjusts the scrollbars. This is important for some event-driven positioning tasks in IE for Windows because the coordinate system for event offset measurements are with respect to the visible area of a page in the browser window. You must add document.body scrolling factors to align event coordinates with body content positions (see the element dragging example in Chapter 6). Starting with IE 5 for Windows, the scrollLeft and scrollTop properties are available for all HTML element objects, but values for unscrollable elements are zero.