The <tr> Element

Technical Summary

Definition, context, and content model

Basic definition of the tr element

Item	Specification summary	Condition / scope
Meaning	A row of cells in a table	The cells carry their own data or heading meaning through td or th
Context	Child of thead, tbody, or tfoot; it may also be a child of table under specific conditions	The table must have no tbody child; the order relative to other children also matters. HTML markup has an additional syntax restriction
Content model	Zero or more td, th, and script-supporting elements	An empty row is permitted by this content model
Content category	Belongs to no specific category	Defined separately as part of the table model
Content attributes	Global attributes	No tr-specific content attributes are defined
End tag	May be omitted under conditions	When immediately followed by another tr, or when the parent has no more content
DOM interface	HTMLTableRowElement	Provides row positions, a cell collection, and cell insertion and deletion

The HTML Standard's content model has a conditional case for a tr child of table, but its HTML syntax conformance rules say that a table must not contain a tr directly. For source markup that does so, the parser inserts a tbody start tag. New markup is easier to read when its row groups are explicit.

Row groups and parser construction

Elements that group table rows

Element	Role in the table	Relationship to rows
thead	Heading part of the table	Contains heading rows
tbody	Main body of the table	Multiple row groups can separate parts of the data
tfoot	Summary part of the table	Contains summary rows

<table>
  <thead><tr><th>Item</th><th>Value</th></tr></thead>
  <tbody><tr><th>Total</th><td>3</td></tr></tbody>
</table>

Each tr in this example has a row group as its parent. A cell with rowspan="0" spans the remaining rows in the same row group, so group boundaries affect the table model when a table has multiple tbody elements.

HTMLTableRowElement and row APIs

Main IDL members for a table row

Member	Value or behavior	Scope / boundary
rowIndex	Position in the table's rows collection	Zero-based; -1 when the row is not associated with a table
sectionRowIndex	Position in the parent table or row group's rows collection	Zero-based; -1 without a matching parent
cells	An HTMLCollection of the row's child td and th elements	Cells inside a nested table are not included
insertCell(index)	Creates and inserts a new td	Default is -1; an out-of-range index throws IndexSizeError
deleteCell(index)	Removes the td or th at the given position	-1 removes the last cell; an out-of-range index throws IndexSizeError

const row = document.querySelector("tbody tr");
row.rowIndex;          // Position in the whole table
row.sectionRowIndex;   // Position in its parent tbody
row.cells;             // This row's th and td elements
row.insertCell(-1);    // Append a td
row.deleteCell(-1);    // Remove the last cell

rowIndex is not a visual column position or a section-local number. When a table has several row groups, keep the whole-table and parent-group indexes separate. If a row is a direct child of a table, sectionRowIndex uses the table's rows collection. Also, insertCell() always creates a td.

Accessibility role

HTML-AAM maps the implicit role of tr to row. Exposure in a browser Accessibility tree, values in a platform API, and speech from an assistive technology are different measurements. The Implementation Evidence below records only the environments and scope actually observed.

Facts / Evidence

Key specification claims are mapped to their conditions and source locations. Implementation observations, WPT runs, and Accessibility role queries are recorded separately below.

Evidence

1. HTML Standard: The tr element — meaning, context, content model, attributes, and row APIs
2. HTML Standard: The table element — row groups and table child ordering
3. HTML Standard: Restrictions on content models — implied tbody for a tr written under table
4. HTML Accessibility API Mappings: tr — implicit row role and platform mappings
5. Web Platform Tests: the-tr-element — row collections, indexes, and cell methods

Implementation Evidence

Specification requirements are kept separate from browser observations, WPT runs, and Accessibility role queries. Each result is limited to its recorded fixture, browser, and test selection.

A browser role/name query is not the same measurement as a platform Accessibility API or screen-reader speech. The observed layer and unmeasured scope stay separate.

Coverage / Open Issues

• ReviewedElement meaning, context and content model, row groups, main HTMLTableRowElement members, and the HTML-AAM role mapping
• OpenImplementation observations cover the selected fixture and one browser environment; all branches for multiple tables, section boundaries, and detached rows remain open
• OpenWPTs outside the selected set, other browser engines, and results against a pinned WPT revision
• OpenPlatform Accessibility APIs, Windows UI Automation, assistive-technology speech, other operating systems, and Expert-gap Review

This is initial coverage. Passing selected checks does not establish the same result for every HTML structure, browser, operating system, or assistive technology.

Related surfaces

For a beginner-friendly row example, see the Yugien tr page. For the section that groups body rows, see How to Use the tbody Element; for summary rows, see How to Use the tfoot Element. The full table model is covered by the table Topic; row-group rules and APIs by the tbody Topic and tfoot Topic; heading cells by th; data cells by td; and the table title by caption.