: The Table Header Element - HTML - MDN Web Docs - Mozilla

Trang chủ » Html Table Scope Col » : The Table Header Element - HTML - MDN Web Docs - Mozilla

Có thể bạn quan tâm

  1. References
  2. HTML
  3. Elements
  4. <th>
Article Actions
  • English (US)
    • Español
    • Français
    • 日本語
    • Português (do Brasil)
    • 中文 (简体)
  • Try it
  • Attributes
  • Usage notes
  • Examples
  • Technical summary
  • Specifications
  • Browser compatibility
  • See also
  1. HTML
  2. Tutorials
  3. HTML basics
  4. Introduction to HTML
    1. Introduction to HTML overview
    2. Getting started with HTML
    3. What's in the head? Metadata in HTML
    4. HTML text fundamentals
    5. Creating hyperlinks
    6. Advanced text formatting
    7. Document and website structure
    8. Debugging HTML
    9. Assessment: Marking up a letter
    10. Assessment: Structuring a page of content
  5. Multimedia and embedding
    1. Multimedia and embedding overview
    2. Images in HTML
    3. Video and audio content
    4. From object to iframe — other embedding technologies
    5. Adding vector graphics to the web
    6. Responsive images
    7. Assessment: Mozilla splash page
  6. HTML tables
    1. HTML tables overview
    2. HTML table basics
    3. HTML table advanced features and accessibility
    4. Assessment: Structuring planet data
  7. References
  8. HTML elements
    1. <a>
    2. <abbr>
    3. <acronym> Deprecated
    4. <address>
    5. <area>
    6. <article>
    7. <aside>
    8. <audio>
    9. <b>
    10. <base>
    11. <bdi>
    12. <bdo>
    13. <big> Deprecated
    14. <blockquote>
    15. <body>
    16. <br>
    17. <button>
    18. <canvas>
    19. <caption>
    20. <center> Deprecated
    21. <cite>
    22. <code>
    23. <col>
    24. <colgroup>
    25. <data>
    26. <datalist>
    27. <dd>
    28. <del>
    29. <details>
    30. <dfn>
    31. <dialog>
    32. <dir> Deprecated
    33. <div>
    34. <dl>
    35. <dt>
    36. <em>
    37. <embed>
    38. <fencedframe> Experimental
    39. <fieldset>
    40. <figcaption>
    41. <figure>
    42. <font> Deprecated
    43. <footer>
    44. <form>
    45. <frame> Deprecated
    46. <frameset> Deprecated
    47. <h1>
    48. <head>
    49. <header>
    50. <hgroup>
    51. <hr>
    52. <html>
    53. <i>
    54. <iframe>
    55. <img>
    56. <input>
    57. <ins>
    58. <kbd>
    59. <label>
    60. <legend>
    61. <li>
    62. <link>
    63. <main>
    64. <map>
    65. <mark>
    66. <marquee> Deprecated
    67. <menu>
    68. <menuitem> Non-standard Deprecated
    69. <meta>
    70. <meter>
    71. <nav>
    72. <nobr> Deprecated
    73. <noembed> Deprecated
    74. <noframes> Deprecated
    75. <noscript>
    76. <object>
    77. <ol>
    78. <optgroup>
    79. <option>
    80. <output>
    81. <p>
    82. <param> Deprecated
    83. <picture>
    84. <plaintext> Deprecated
    85. <portal> Experimental
    86. <pre>
    87. <progress>
    88. <q>
    89. <rb> Deprecated
    90. <rp>
    91. <rt>
    92. <rtc> Deprecated
    93. <ruby>
    94. <s>
    95. <samp>
    96. <script>
    97. <search>
    98. <section>
    99. <select>
    100. <slot>
    101. <small>
    102. <source>
    103. <span>
    104. <strike> Deprecated
    105. <strong>
    106. <style>
    107. <sub>
    108. <summary>
    109. <sup>
    110. <table>
    111. <tbody>
    112. <td>
    113. <template>
    114. <textarea>
    115. <tfoot>
    116. <th>
    117. <thead>
    118. <time>
    119. <title>
    120. <tr>
    121. <track>
    122. <tt> Deprecated
    123. <u>
    124. <ul>
    125. <var>
    126. <video>
    127. <wbr>
    128. <xmp> Deprecated
  9. Global attributes
    1. accesskey
    2. anchor Experimental Non-standard
    3. autocapitalize
    4. autofocus
    5. class
    6. contenteditable
    7. data-*
    8. dir
    9. draggable
    10. enterkeyhint
    11. exportparts
    12. hidden
    13. id
    14. inert
    15. inputmode
    16. is
    17. itemid
    18. itemprop
    19. itemref
    20. itemscope
    21. itemtype
    22. lang
    23. nonce
    24. part
    25. popover
    26. slot
    27. spellcheck
    28. style
    29. tabindex
    30. title
    31. translate
    32. virtualkeyboardpolicy Experimental
  10. Attributes
    1. accept
    2. autocomplete
    3. capture
    4. crossorigin
    5. dirname
    6. disabled
    7. elementtiming
    8. for
    9. max
    10. maxlength
    11. min
    12. minlength
    13. multiple
    14. pattern
    15. placeholder
    16. readonly
    17. rel
    18. required
    19. size
    20. step
  11. <input> types
    1. <input type="button">
    2. <input type="checkbox">
    3. <input type="color">
    4. <input type="date">
    5. <input type="datetime-local">
    6. <input type="email">
    7. <input type="file">
    8. <input type="hidden">
    9. <input type="image">
    10. <input type="month">
    11. <input type="number">
    12. <input type="password">
    13. <input type="radio">
    14. <input type="range">
    15. <input type="reset">
    16. <input type="search">
    17. <input type="submit">
    18. <input type="tel">
    19. <input type="text">
    20. <input type="time">
    21. <input type="url">
    22. <input type="week">
  12. Guides
    1. Content categories
    2. Block-level elements
    3. Inline elements
    4. Quirks Mode and Standards Mode
    5. Date and time formats used in HTML
    6. Constraint validation
    7. Microdata
    8. Microformats
    9. Viewport meta tag
    10. Allowing cross-origin use of images and canvas
  • Try it
  • Attributes
  • Usage notes
  • Examples
  • Technical summary
  • Specifications
  • Browser compatibility
  • See also

The <th> HTML element defines a cell as the header of a group of table cells and may be used as a child of the <tr> element. The exact nature of this group is defined by the scope and headers attributes.

Try it

Attributes

This element includes the global attributes.

abbr

A short, abbreviated description of the header cell's content provided as an alternative label to use for the header cell when referencing the cell in other contexts. Some user-agents, such as speech readers, may present this description before the content itself.

colspan

A non-negative integer value indicating how many columns the header cell spans or extends. The default value is 1. User agents dismiss values higher than 1000 as incorrect, defaulting such values to 1.

headers

A list of space-separated strings corresponding to the id attributes of the <th> elements that provide the headers for this header cell.

rowspan

A non-negative integer value indicating how many rows the header cell spans or extends. The default value is 1; if its value is set to 0, the header cell will extends to the end of the table grouping section (<thead>, <tbody>, <tfoot>, even if implicitly defined), that the <th> belongs to. Values higher than 65534 are clipped at 65534.

scope

Defines the cells that the header (defined in the <th>) element relates to. Possible enumerated values are:

  • row: the header relates to all cells of the row it belongs to;
  • col: the header relates to all cells of the column it belongs to;
  • rowgroup: the header belongs to a rowgroup and relates to all of its cells;
  • colgroup: the header belongs to a colgroup and relates to all of its cells.

If the scope attribute is not specified, or its value is not row, col, rowgroup, or colgroup, then browsers automatically select the set of cells to which the header cell applies.

Deprecated attributes

The following attributes are deprecated and should not be used. They are documented below for reference when updating existing code and for historical interest only.

align Deprecated

Specifies the horizontal alignment of the header cell. The possible enumerated values are left, center, right, justify, and char. When supported, the char value aligns the textual content on the character defined in the char attribute and the offset defined by the charoff attribute. Use the text-align CSS property instead, as this attribute is deprecated.

axis Deprecated

Contains a list of space-separated strings, each corresponding to the id attribute of a group of cells that the header cell applies to. Use the scope attribute instead, as this attribute is deprecated.

bgcolor Deprecated

Defines the background color of the header cell. The value is an HTML color; either a 6-digit hexadecimal RGB code, prefixed by a '#', or a color keyword. Other CSS <color> values are not supported. Use the background-color CSS property instead, as this attribute is deprecated.

char Deprecated

Does nothing. It was originally intended to specify the alignment of the content to a character of the header cell. Typical values for this include a period (.) when attempting to align numbers or monetary values. If align is not set to char, this attribute is ignored.

charoff Deprecated

Does nothing. It was originally intended to specify the number of characters to offset the header cell content from the alignment character specified by the char attribute.

height Deprecated

Defines a recommended header cell height. Use the height CSS property instead, as this attribute is deprecated.

valign Deprecated

Specifies the vertical alignment of the header cell. The possible enumerated values are baseline, bottom, middle, and top. Use the vertical-align CSS property instead, as this attribute is deprecated.

width Deprecated

Defines a recommended header cell width. Use the width CSS property instead, as this attribute is deprecated.

Usage notes

  • The <th> may only be used within a <tr> element.
  • In simple contexts, using the scope attribute on header cells (<th> elements) is redundant because scope is inferred. However, certain assistive technologies may fail to infer correctly, so specifying header scope may improve user experiences.
  • When using the colspan and rowspan attributes to span header cells across multiple columns and rows, cells without these attributes defined (with a default value of 1) are automatically fitted into free available spaces in the table structure that span 1x1 cells, as illustrated in the following figure: Illustration demonstrating column and row spanning of table cells: cells 1, 3, and 4 spanning two rows; cell 2 spanning two columns; cells 5 and 6 fitting into the available cells that are the second and third columns in the second row

    Note: These attributes must not be used to overlap cells.

Examples

See <table> for a complete table example introducing common standards and best practices.

Basic column and row headers

This example uses <th> elements to introduce column and row headers in a basic table structure.

HTML

The first row (<tr> element) contains the column headers (<th> elements), which act as "titles" for the columns to make it easier to understand the information in the columns and identify the data. To indicate that each column header relates to all cells in the corresponding column, the scope attribute is set to col (column).

The remaining rows contain the main data of the table. Each of these rows has a row header (<th> element) introduced as the first cell. This creates a column with row headers as the first column of the table. Similar to the column headers, the scope attribute is set to row to specify which cells each row header relates to, which in the example below are all data cells (<td> elements) in each row.

Note: Normally, the grouping elements <thead> and <tbody> are used to group rows with headers into the respective table head and body sections. These elements are omitted in this example to reduce complexity and enable focusing on the use of header cells.

html<table> <tr> <th scope="col">Symbol</th> <th scope="col">Code word</th> <th scope="col">Pronunciation</th> </tr> <tr> <th scope="row">A</th> <td>Alfa</td> <td>AL fah</td> </tr> <tr> <th scope="row">B</th> <td>Bravo</td> <td>BRAH voh</td> </tr> <tr> <th scope="row">C</th> <td>Charlie</td> <td>CHAR lee</td> </tr> <tr> <th scope="row">D</th> <td>Delta</td> <td>DELL tah</td> </tr> </table>

CSS

Some basic CSS is used to style the table and its cells. We use CSS attribute selectors to target header cells based on their scope attribute values, highlighting column and row headers (<th> elements) and differentiating them each other and from the data cells (<td>).

cssth, td { border: 1px solid rgb(160 160 160); padding: 8px 10px; } th[scope="col"] { background-color: #505050; color: #fff; } th[scope="row"] { background-color: #d6ecd4; } tr:nth-of-type(odd) td { background-color: #eee; } table { border-collapse: collapse; border: 2px solid rgb(140 140 140); font-family: sans-serif; font-size: 0.8rem; letter-spacing: 1px; }

Result

Column and row spanning

This example extends and enhances the basic table from the previous example by adding a second row for additional column headers.

HTML

An additional table row (<tr> element) is added as the second header row of the table with two additional column headers (<th> elements). In this way, the "Pronunciation" column is split into two columns, one for the IPA (International Phonetic Alphabet) notation and one for the respelling (the original pronunciation column). The corresponding data cells (<td> elements) are added to each subsequent row.

As shown in the usage notes, the colspan and rowspan attributes can be used for the <th> elements to allocate the header cells to the correct columns and rows. To achieve a "two-row" header in the table structure, the first two header cells within the first <tr> element are spanned across two rows. The third header cell is spanned two columns wide (remaining in the first row). This setup leaves two available areas in the third and fourth columns in the second row, where the two headers within the second <tr> element are automatically placed, with the default value being 1 for the colspan and rowspan attributes.

Note: Normally, <thead> and <tbody> elements are used to group rows with headers into the respective table head and body sections. This is not implemented in this example to focus on the headers and spanning and reduce the example's complexity.

html<table> <tr> <th scope="col" rowspan="2">Symbol</th> <th scope="col" rowspan="2">Code word</th> <th scope="col" colspan="2">Pronunciation</th> </tr> <tr> <th scope="col">IPA</th> <th scope="col">Respelling</th> </tr> <tr> <th scope="row">A</th> <td>Alfa</td> <td>ˈælfa</td> <td>AL fah</td> </tr> <tr> <th scope="row">B</th> <td>Bravo</td> <td>ˈbraːˈvo</td> <td>BRAH voh</td> </tr> <tr> <th scope="row">C</th> <td>Charlie</td> <td>ˈtʃɑːli</td> <td>CHAR lee</td> </tr> <tr> <th scope="row">D</th> <td>Delta</td> <td>ˈdeltɑ</td> <td>DELL tah</td> </tr> </table>

CSS

The CSS is unchanged from the previous example.

table { border-collapse: collapse; border: 2px solid rgb(140 140 140); font-family: sans-serif; font-size: 0.8rem; letter-spacing: 1px; } th, td { border: 1px solid rgb(160 160 160); padding: 8px 10px; } th[scope="col"] { background-color: #505050; color: #fff; } th[scope="row"] { background-color: #d6ecd4; } tr:nth-of-type(odd) td { background-color: #eee; }

Result

Associate header cells with other header cells

For more complex relationships between header cells, using th elements with the scope attribute alone may not be sufficient for assistive technologies, especially screen readers.

HTML

To improve the accessibility of the previous example and to allow screen readers, for example, to speak the headers associated with each header cell, the headers attribute can be introduced along with id attributes. Because of the way the "Pronunciation" column is split into two columns in the example, introducing a "two row" header, assistive technologies such as screen readers may not be able to identify which additional header cells (th elements) the "Pronunciation" header cell is related to and vice versa. Therefore, the headers attribute is used on the "Pronunciation", "IPA", and "Respelling" header cells to associate the related header cells based on the values of the unique identifiers from the added id attributes in the form of a space-separated list.

Note: It's recommended to use more descriptive and useful values for the id attribute. Each id in a document must be unique to that document. In this example, the id values are single characters to maintain focus on the concept of the headers attribute.

html<table> <tr> <th scope="col" rowspan="2">Symbol</th> <th scope="col" rowspan="2">Code word</th> <th scope="col" colspan="2" id="p" headers="i r">Pronunciation</th> </tr> <tr> <th scope="col" id="i" headers="p">IPA</th> <th scope="col" id="r" headers="p">Respelling</th> </tr> <tr> <th scope="row">A</th> <td>Alfa</td> <td>ˈælfa</td> <td>AL fah</td> </tr> <tr> <th scope="row">B</th> <td>Bravo</td> <td>ˈbraːˈvo</td> <td>BRAH voh</td> </tr> <tr> <th scope="row">C</th> <td>Charlie</td> <td>ˈtʃɑːli</td> <td>CHAR lee</td> </tr> <tr> <th scope="row">D</th> <td>Delta</td> <td>ˈdeltɑ</td> <td>DELL tah</td> </tr> </table>

Result

The visual result is unchanged from the previous example table.

Technical summary

Content categories None.
Permitted content Flow content, but with no header, footer, sectioning content, or heading content descendants.
Tag omission The start tag is mandatory.The end tag may be omitted, if it is immediately followed by a <th> or <td> element or if there are no more data in its parent element.
Permitted parents A <tr> element.
Implicit ARIA role columnheader or rowheader
Permitted ARIA roles Any
DOM interface HTMLTableCellElement

Specifications

Specification
HTML Standard # the-th-element

Browser compatibility

BCD tables only load in the browser

See also

  • Learn: HTML tables
  • <caption>, <col>, <colgroup>, <table>, <tbody>, <td>, <tfoot>, <thead>, <tr>: Other table-related elements
  • background-color: CSS property to set the background color of each header cell
  • border: CSS property to control borders of header cells
  • height: CSS property to control the recommended header cell height
  • text-align: CSS property to horizontally align each header cell content
  • vertical-align: CSS property to vertically align each header cell content
  • width: CSS property to control the recommended header cell width
  • :nth-of-type, :first-of-type, :last-of-type: CSS pseudo-classes to select the desired header cells

Help improve MDN

Was this page helpful to you?YesNoLearn how to contribute.

This page was last modified on Apr 26, 2024 by MDN contributors.

View this page on GitHub • Report a problem with this content

Từ khóa » Html Table Scope Col