t - Web APIs | MDN

• Skip to main content
• Skip to search
• Skip to select language

1. References
2. Web APIs
3. HTMLImageElement
4. alt

Article Actions

• English (US)
  • Remember language
  • Deutsch
  • 日本語

• Value
• Usage notes
• Examples
• Specifications
• Browser compatibility

1. HTML DOM API
2. HTMLImageElement
3. Constructor
   1. Image()
4. Instance properties
   1. align Deprecated
   2. alt
   3. attributionSrc Experimental
   4. border Deprecated
   5. complete
   6. crossOrigin
   7. currentSrc
   8. decoding
   9. fetchPriority
   10. height
   11. hspace Deprecated
   12. isMap
   13. loading
   14. longDesc Deprecated
   15. name Deprecated
   16. naturalHeight
   17. naturalWidth
   18. referrerPolicy
   19. sizes
   20. src
   21. srcset
   22. useMap
   23. vspace Deprecated
   24. width
   25. x
   26. y
5. Instance methods
   1. decode()
6. Inheritance
   1. HTMLElement
   2. Element
   3. Node
   4. EventTarget
7. Related pages for HTML DOM
   1. BeforeUnloadEvent
   2. DOMStringMap
   3. ErrorEvent
   4. HTMLAnchorElement
   5. HTMLAreaElement
   6. HTMLAudioElement
   7. HTMLBRElement
   8. HTMLBaseElement
   9. HTMLBodyElement
   10. HTMLButtonElement
   11. HTMLCanvasElement
   12. HTMLDListElement
   13. HTMLDataElement
   14. HTMLDataListElement
   15. HTMLDialogElement
   16. HTMLDivElement
   17. HTMLDocument
   18. HTMLElement
   19. HTMLEmbedElement
   20. HTMLFieldSetElement
   21. HTMLFormControlsCollection
   22. HTMLFormElement
   23. HTMLFrameSetElement Deprecated
   24. HTMLHRElement
   25. HTMLHeadElement
   26. HTMLHeadingElement
   27. HTMLHtmlElement
   28. HTMLIFrameElement
   29. HTMLInputElement
   30. HTMLLIElement
   31. HTMLLabelElement
   32. HTMLLegendElement
   33. HTMLLinkElement
   34. HTMLMapElement
   35. HTMLMediaElement
   36. HTMLMenuElement
   37. HTMLMetaElement
   38. HTMLMeterElement
   39. HTMLModElement
   40. HTMLOListElement
   41. HTMLObjectElement
   42. HTMLOptGroupElement
   43. HTMLOptionElement
   44. HTMLOptionsCollection
   45. HTMLOutputElement
   46. HTMLParagraphElement
   47. HTMLPictureElement
   48. HTMLPreElement
   49. HTMLProgressElement
   50. HTMLQuoteElement
   51. HTMLScriptElement
   52. HTMLSelectElement
   53. HTMLSourceElement
   54. HTMLSpanElement
   55. HTMLStyleElement
   56. HTMLTableCaptionElement
   57. HTMLTableCellElement
   58. HTMLTableColElement
   59. HTMLTableElement
   60. HTMLTableRowElement
   61. HTMLTableSectionElement
   62. HTMLTemplateElement
   63. HTMLTextAreaElement
   64. HTMLTimeElement
   65. HTMLTitleElement
   66. HTMLTrackElement
   67. HTMLUListElement
   68. HTMLUnknownElement
   69. HTMLVideoElement
   70. HashChangeEvent
   71. History
   72. ImageData
   73. Location
   74. MessageChannel
   75. MessageEvent
   76. MessagePort
   77. Navigator
   78. PageRevealEvent
   79. PageSwapEvent
   80. PageTransitionEvent
   81. Plugin Deprecated
   82. PluginArray Deprecated
   83. PromiseRejectionEvent
   84. RadioNodeList
   85. UserActivation
   86. ValidityState
   87. Window
   88. WorkletGlobalScope

• Value
• Usage notes
• Examples
• Specifications
• Browser compatibility

The HTMLImageElement property alt provides fallback (alternate) text to display when the image specified by the <img> element is not loaded.

This may be the case because of an error, because the user has disabled the loading of images, or because the image hasn't finished loading yet.

Perhaps the most important reason to use the alt property is to support accessibility, as the alt text may be used by screen readers and other assistive technologies to help people with a disability make full use of your content. It will be read aloud or sent to a braille output device, for example, to support blind or visually impaired users.

Think of it like this: When choosing alt strings for your images, imagine what you would say when reading the page to someone over the phone without mentioning that there's an image on the page.

The alternate text is displayed in the space the image would occupy and should be able to take the place of the image without altering the meaning of the page.

Value

A string which contains the alternate text to display when the image is not loaded or for use by assistive devices.

The alt attribute is officially mandatory; it's meant to always be specified. If the image doesn't require a fallback (such as for an image which is decorative or an advisory icon of minimal importance), you may specify an empty string (""). For compatibility reasons, browsers generally will accept an image without an alt attribute, but you should try to get into the habit of using it.

Usage notes

The fundamental guideline for the alt attribute is that every image's alternate text should be able to replace the image without altering the meaning of the page. You should never use alt for text that could be construed as a caption or title. There are separate attributes and elements designed for those purposes.

Examples

Beyond that, there are additional guidelines for using alt appropriately which vary depending on what the image is being used for. These are shown in the examples below.

Decorative images

Images with no semantic meaning—such as those which are solely decorative—or of limited informational value, should have their alt attributes set to the empty string (""). This is shown in the example below.

HTML

In the HTML for this example, shown below, the <img> element includes the alt property, which will prevent the image from having any alternate text, since it's a decorative detail.

html<div class="container"> <div class="left-margin"> <img src="margin-flourish.svg" alt="" /> </div> <div class="contents"> <p> Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque quis orci ligula. Lorem ipsum dolor sit amet, consectetur adipiscing elit. In ac neque libero. Vivamus consectetur rhoncus elit eget porta. Etiam pulvinar ex id sapien laoreet, quis aliquet odio lobortis. Nam ac mauris at risus laoreet cursus vitae et sapien. Etiam molestie auctor eros, ac porta risus scelerisque sit amet. Ut nunc neque, porta eu auctor at, tempor et arcu. </p> </div> </div>

CSS

The CSS for this example sets up the styles for the layout as shown in the result below.

cssbody { margin: 0; padding: 0; } p { margin-block-start: 0; margin-block-end: 1em; margin-top: 0; margin-bottom: 1em; } .container { width: 100vh; height: 95vh; font: 16px Arial, Helvetica, sans-serif; } .left-margin { background-color: rgb(241 240 237); width: 9em; height: 100%; float: left; margin-right: 5px; padding-right: 1em; display: flex; align-items: center; justify-content: center; } .left-margin img { width: 6em; } .contents { background-color: rgb(241 240 235); height: 100%; margin-left: 2em; padding-top: 1em; padding-left: 2em; padding-right: 1em; }

Result

Images used as buttons

When using an image as a button (by using it as the only visible child of an <a> element representing a hyperlink), the alt attribute must be used to convey the purpose of the button. In other words, it should be the same text you would use in a textual button to serve the same purpose.

For example, in the snippet of HTML below, a toolbar which uses icon images as link labels provides alt attributes for each giving a textual label to use instead of the icon when the icons cannot be or are intentionally not used.

html<li class="toolbar" aria-role="toolbar"> <a href="songs.html" aria-role="button"> <img src="songicon.svg" alt="Songs" /> </a> <a href="albums.html" aria-role="button"> <img src="albumicon.svg" alt="Albums" /></a> <a href="artists.html" aria-role="button"> <img src="artisticon.svg" alt="Artists" /> </a> <a href="playlists.html" aria-role="button"> <img src="playlisticon.svg" alt="Playlists" /> </a> </li>

Images containing diagrams or maps

When an image contains information presented as a diagram, chart, graph, or map, the alt text should provide the same information, at least in summary form. This is true whether the /me image is in a bitmapped format such as PNG or JPEG or in a vector format like SVG.

• For a map, the alt text could be directions to the place indicated by the map, similarly to how you would explain it verbally.
• For a chart, the text could describe the items in the chart and their values.
• For a diagram, the text could be an explanation of the concept presented by the diagram.

Keep in mind that any text included in diagrams and charts presented in SVG format may be read by screen readers. This may impact the decisions you make when writing the alt text for the diagram.

Icons or logos

Logos (such as corporate or brand logos) and informational icons should use the corresponding text in their alt strings. That is, if an image is a corporate logo, the alt text should be the name of the company. If the image is an icon representing a status or other information, the text should be the name of that state.

For example, if an image is a badge that's shown on a page to indicate that the content of the page is new and has been updated recently, the corresponding alt text might be "Updated Recently" or even "Updated on 27 August 2019".

In this example, a starburst image with the word "New!" is used to indicate that an article is about something new (and probably supposedly also exciting). The alt attribute is set to New Page! to allow that text to be displayed in place of the image if the image isn't available. It is also available to be read by screen readers.

HTML

The HTML below creates a snippet of content from a site using the described icon. Note the use of the alt attribute on the <img>, providing a good substitution string to use in case the image doesn't load.

html<div class="container"> <img src="https://www.bitstampede.com/mdn-test/new-page.svg" alt="New Page!" class="pageinfo-badge" /> <p class="contents"> Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque quis orci ligula. Lorem ipsum dolor sit amet, consectetur adipiscing elit. In ac neque libero. Vivamus consectetur rhoncus elit eget porta. Etiam pulvinar ex id sapien laoreet, quis aliquet odio lobortis. Nam ac mauris at risus laoreet cursus vitae et sapien. Etiam molestie auctor eros, ac porta risus scelerisque sit amet. Ut nunc neque, porta eu auctor at, tempor et arcu. </p> </div>

CSS

The main feature of the CSS here is the use of clip-path and shape-outside to wrap the text around the icon in an appealing way.

css.container { max-width: 500px; } .pageinfo-badge { width: 9em; padding-right: 1em; float: left; clip-path: polygon( 100% 0, 100% 50%, 90% 70%, 80% 80%, 70% 90%, 50% 100%, 0 100%, 0 0 ); shape-outside: polygon( 100% 0, 100% 50%, 90% 70%, 80% 80%, 70% 90%, 50% 100%, 0 100%, 0 0 ); } .contents { margin-top: 1em; font: 16px Arial, Helvetica, Verdana, sans-serif; }

Result

Other images

Images showing objects or scenes should have alt text describing what's seen in the image. A photo of a yellow teapot might literally have its alt attribute set to "A yellow teapot".

Specifications

Specification
HTML Standard # dom-img-alt

Browser compatibility

BCD tables only load in the browser

Help improve MDN

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

This page was last modified on Sep 24, 2024 by MDN contributors.

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