id

The id global attribute defines an identifier (ID) which must be unique in the whole document. Its purpose is to identify the element when linking (using a fragment identifier), scripting, or styling (with CSS).

This attribute's value is an opaque string: this means that web authors must not use it to convey human-readable information.

id's value must not contain whitespace (spaces, tabs etc.). Browsers treat non-conforming IDs that contain whitespace as if the whitespace is part of the ID. In contrast to the class attribute, which allows space-separated values, elements can only have one single ID value.

Note: Using characters except ASCII letters, digits, '_', '-' and '.' may cause compatibility problems, as they weren't allowed in HTML 4. Though this restriction has been lifted in HTML5, an ID should start with a letter for compatibility.

Specifications

Specification Status Comment
HTML Living Standard
The definition of 'id' in that specification.		 Living Standard No change from latest snapshot, HTML 5.1
HTML 5.1
The definition of 'id' in that specification.		 Recommendation Snapshot of HTML Living Standard, no change from HTML5
HTML5
The definition of 'id' in that specification.		 Recommendation Snapshot of HTML Living Standard, now accept '_', '-' and '.' if not at the beginning of the id. It is also a true global attribute.
HTML 4.01 Specification
The definition of 'id' in that specification.		 Recommendation Supported on all elements but <base>, <head>, <html>, <meta>, <script>, <style>, and <title>.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
idChrome Full support YesEdge Full support 12Firefox Full support 32
Full support 32
No support ? — 32
Notes
Notes id is a true global attribute only since Firefox 32.
IE Full support YesOpera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesFirefox Android Full support 32
Full support 32
No support ? — 32
Notes
Notes id is a true global attribute only since Firefox 32.
Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yes

Legend

Full support  
Full support
See implementation notes.
See implementation notes.

See also

Related Topics
  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. References:
  7. HTML elements
    1. <a>
    2. <abbr>
    3. <acronym>
    4. <address>
    5. <applet>
    6. <area>
    7. <article>
    8. <aside>
    9. <audio>
    10. <b>
    11. <base>
    12. <basefont>
    13. <bdi>
    14. <bdo>
    15. <bgsound>
    16. <big>
    17. <blink>
    18. <blockquote>
    19. <body>
    20. <br>
    21. <button>
    22. <canvas>
    23. <caption>
    24. <center>
    25. <cite>
    26. <code>
    27. <col>
    28. <colgroup>
    29. <command>
    30. <content>
    31. <data>
    32. <datalist>
    33. <dd>
    34. <del>
    35. <details>
    36. <dfn>
    37. <dialog>
    38. <dir>
    39. <div>
    40. <dl>
    41. <dt>
    42. <element>
    43. <em>
    44. <embed>
    45. <fieldset>
    46. <figcaption>
    47. <figure>
    48. <font>
    49. <footer>
    50. <form>
    51. <frame>
    52. <frameset>
    53. <h1>
    54. <head>
    55. <header>
    56. <hgroup>
    57. <hr>
    58. <html>
    59. <i>
    60. <iframe>
    61. <image>
    62. <img>
    63. <input>
    64. <ins>
    65. <isindex>
    66. <kbd>
    67. <keygen>
    68. <label>
    69. <legend>
    70. <li>
    71. <link>
    72. <listing>
    73. <main>
    74. <map>
    75. <mark>
    76. <marquee>
    77. <menu>
    78. <menuitem>
    79. <meta>
    80. <meter>
    81. <multicol>
    82. <nav>
    83. <nextid>
    84. <nobr>
    85. <noembed>
    86. <noframes>
    87. <noscript>
    88. <object>
    89. <ol>
    90. <optgroup>
    91. <option>
    92. <output>
    93. <p>
    94. <param>
    95. <picture>
    96. <plaintext>
    97. <pre>
    98. <progress>
    99. <q>
    100. <rb>
    101. <rp>
    102. <rt>
    103. <rtc>
    104. <ruby>
    105. <s>
    106. <samp>
    107. <script>
    108. <section>
    109. <select>
    110. <shadow>
    111. <slot>
    112. <small>
    113. <source>
    114. <spacer>
    115. <span>
    116. <strike>
    117. <strong>
    118. <style>
    119. <sub>
    120. <summary>
    121. <sup>
    122. <table>
    123. <tbody>
    124. <td>
    125. <template>
    126. <textarea>
    127. <tfoot>
    128. <th>
    129. <thead>
    130. <time>
    131. <title>
    132. <tr>
    133. <track>
    134. <tt>
    135. <u>
    136. <ul>
    137. <var>
    138. <video>
    139. <wbr>
    140. <xmp>
  8. Global attributes
    1. accesskey
    2. autocapitalize
    3. class
    4. contenteditable
    5. contextmenu
    6. data-*
    7. dir
    8. draggable
    9. dropzone
    10. hidden
    11. id
    12. inputmode
    13. is
    14. itemid
    15. itemprop
    16. itemref
    17. itemscope
    18. itemtype
    19. lang
    20. part
    21. slot
    22. spellcheck
    23. style
    24. tabindex
    25. title
    26. translate
    27. x-ms-acceleratorkey
    28. x-ms-format-detection
  9. <input> types
    1. <input type="button">
    2. <input type="checkbox">
    3. <input type="color">
    4. <input type="date">
    5. <input type="datetime">
    6. <input type="datetime-local">
    7. <input type="email">
    8. <input type="file">
    9. <input type="hidden">
    10. <input type="image">
    11. <input type="month">
    12. <input type="number">
    13. <input type="password">
    14. <input type="radio">
    15. <input type="range">
    16. <input type="reset">
    17. <input type="search">
    18. <input type="submit">
    19. <input type="tel">
    20. <input type="text">
    21. <input type="time">
    22. <input type="url">
    23. <input type="week">
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