A treehead defines the header row of the tree. It is much like the treerow element and should contain treecell elements.

Attributes inherited from XUL Element

Determines the horizontal alignment of the children of the treehead.

• left: The elements are aligned on their left edges.
• center: The elements are centered.
• right: The elements are aligned on their right edges.

In the treehead is placed inside a horizontally oriented box, autostretch determines whether the treehead stretches vertically to fit the given space. For vertically oriented boxes, determines whether the treehead stretches horizontally to fit the given space. Stetching in the opoosite direction is controlled with the flex attribute.

• never: The treehead is never stretched and is displayed at the size specified by its width and height attributes or by the CSS width and height properties.
• always: The treehead stretches to fill the given space.

If true, then the treehead is collapsed and does not appear. It is equavalent to setting the CSS visibility property to collapsed.

If the label of the treehead is too small to fit in its given space, the text will be cropped on the side specified by the crop attribute. An ellipsis will be placed in place of the cropped text.

• left: The text will be cropped on its left side.
• right: The text will be cropped on its right side.
• center: The text will be cropped on both sides.
• none: The text will be not be cropped using an ellipsis. However, the text will simply be cut off if it too large. The side depends on the CSS text alignment.

If true, extra borders are drawn around the element and all its descendants. This can be used to determine orientation and where flexible elements are. If debug mode is enabled for a box, horizontal oriented boxes are displayed with a blue border and vertical boxes are displayed with a red border. The border above the element will be straight for non-flexible elements and wavy for flexible elements.

Indicates the flexibility of the treehead. Flexible elements grow and shrink to fit their given space. The actual value is not relevant unless there are other flexible elements with-in the same container. Elements with larger flex values will grow more than elements with lower flex values, at the ratio determined by the two elements.

The height of the treehead in pixels. It is recommended to use the CSS height property instead.

For elements placed within a bulletinboard, specifies the position of the left edge of the treehead.

Used to specify whether the children of the treehead element are oriented horizontally or vertically.

• horizontal: Child elements of the treehead are placed next to each other in a row in the order that they appear in the XUL source.
• vertical: Child elements of the treehead are placed under to each other in a column in the order that they appear in the XUL source.

For elements placed within a bulletinboard, specifies the position of the top edge of the treehead.

Determines the vertical alignment of the children of the treehead.

• top: Elements are aligned by their top edges.
• middle: Elements are centered vertically.
• bottom: Elements are aligned by their bottom edges.
• baseline: Elements are aligned by their text baseline.

The width of the treehead in pixels. It is recommended to use the CSS width property instead.