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is global attribute allows you to specify that a standard HTML element should behave like a defined custom built-in element (see Using custom elements 了解更多细节)。

This attribute can only be used if the specified custom element name has been successfully defined in the current document, and extends the element type it is being applied to.

范例

The following code is taken from our word-count-web-component example ( see it live also ). 

// Create a class for the element
class WordCount extends HTMLParagraphElement {
  constructor() {
    // Always call super first in constructor
    super();
    // Constructor contents ommitted for brevity
    ...
  }
}
// Define the new element
customElements.define('word-count', WordCount, { extends: 'p' });
					
<p is="word-count"></p>

规范

规范 状态 注释
HTML 实时标准
The definition of 'is' in that specification. 		实时标准

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据
桌面 移动
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
is Chrome 完整支持 67 Edge 完整支持 79 Firefox 完整支持 63
完整支持 63
不支持 59 — 63 Disabled
Disabled From version 59 until version 63 (exclusive): this feature is behind the dom.webcomponents.customelements.enabled preference (needs to be set to true ). To change preferences in Firefox, visit about:config.
不支持 ? — 59 Disabled
Disabled Until version 59 (exclusive): this feature is behind the dom.webcomponents.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.
IE 不支持 No Opera 完整支持 55 Safari 不支持 No WebView Android 完整支持 67 Chrome Android 完整支持 67 Firefox Android 完整支持 63
完整支持 63
不支持 59 — 63 Disabled
Disabled From version 59 until version 63 (exclusive): this feature is behind the dom.webcomponents.customelements.enabled preference (needs to be set to true ). To change preferences in Firefox, visit about:config.
不支持 ? — 59 Disabled
Disabled Until version 59 (exclusive): this feature is behind the dom.webcomponents.enabled preference (needs to be set to true ) 和 preference (needs to be set to ). To change preferences in Firefox, visit about:config.
Opera Android 完整支持 48 Safari iOS 不支持 No Samsung Internet Android 完整支持 9.0

图例

完整支持

完整支持

不支持

不支持

用户必须明确启用此特征。

用户必须明确启用此特征。

另请参阅

元数据

  • 最后修改：
  1. HTML
  2. 教程：
  3. HTML 基础
  4. HTML 介绍
    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. 多媒体和嵌入
    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. 参考：
  7. HTML 元素
    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. 全局属性
    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> 类型
    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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