Html.Attributes

Helper functions for HTML attributes. They are organized roughly by category. Each attribute is labeled with the HTML tags it can be used with, so just search the page for video if you want video stuff.

Primitives

style : String -> String -> Attribute msg

Specify a style.

greeting : Node msg
greeting =
  div
    [ style "background-color" "red"
    , style "height" "90px"
    , style "width" "100%"
    ]
    [ text "Hello!"
    ]

There is no Html.Styles module because best practices for working with HTML suggest that this should primarily be specified in CSS files. So the general recommendation is to use this function lightly.

property : String -> Value -> Attribute msg

Create properties, like saying domNode.className = 'greeting' in JavaScript.

import Json.Encode as Encode

class : String -> Attribute msg
class name =
  property "className" (Encode.string name)

Read more about the difference between properties and attributes here.

attribute : String -> String -> Attribute msg

Create attributes, like saying domNode.setAttribute('class', 'greeting') in JavaScript.

class : String -> Attribute msg
class name =
  attribute "class" name

Read more about the difference between properties and attributes here.

map : (a -> msg) -> Attribute a -> Attribute msg

Transform the messages produced by an Attribute.

Super Common Attributes

class : String -> Attribute msg

Often used with CSS to style elements with common properties.

Note: You can have as many class and classList attributes as you want. They all get applied, so if you say [ class "notice", class "notice-seen" ] you will get both classes!

classList : Array { class : String, enabled : Bool } -> Attribute msg

This function makes it easier to build a space-separated class attribute. Each class can easily be added and removed depending on the boolean value it is paired with. For example, maybe we want a way to view notices:

viewNotice : Notice -> Html msg
viewNotice notice =
  div
    [ classList
        [ { class = "notice", enabled = True }
        , { class = "notice-important", enabled = notice.isImportant }
        , { class = "notice-seen", enabled = notice.isSeen }
        ]
    ]
    [ text notice.content ]

Note: You can have as many class and classList attributes as you want. They all get applied, so if you say [ class "notice", class "notice-seen" ] you will get both classes!

id : String -> Attribute msg

Often used with CSS to style a specific element. The value of this attribute must be unique.

title : String -> Attribute msg

Text to be displayed in a tooltip when hovering over the element.

hidden : Bool -> Attribute msg

Indicates the relevance of an element.

Inputs

type_ : String -> Attribute msg

Defines the type of a button, checkbox, input, embed, menu, object, script, source, or style.

value : String -> Attribute msg

Defines a default value which will be displayed in a button, option, input, li, meter, progress, or param.

checked : Bool -> Attribute msg

Indicates whether an input of type checkbox is checked.

placeholder : String -> Attribute msg

Provides a hint to the user of what can be entered into an input or textarea.

selected : Bool -> Attribute msg

Defines which option will be selected on page load.

Input Helpers

accept : String -> Attribute msg

List of types the server accepts, typically a file type. For form and input.

acceptCharset : String -> Attribute msg

List of supported charsets in a form.

action : String -> Attribute msg

The URI of a program that processes the information submitted via a form.

autocomplete : Bool -> Attribute msg

Indicates whether a form or an input can have their values automatically completed by the browser.

autofocus : Bool -> Attribute msg

The element should be automatically focused after the page loaded. For button, input, select, and textarea.

disabled : Bool -> Attribute msg

Indicates whether the user can interact with a button, fieldset, input, optgroup, option, select or textarea.

enctype : String -> Attribute msg

How form data should be encoded when submitted with the POST method. Options include: application/x-www-form-urlencoded, multipart/form-data, and text/plain.

list : String -> Attribute msg

Associates an input with a datalist tag. The datalist gives some pre-defined options to suggest to the user as they interact with an input. The value of the list attribute must match the id of a datalist node. For input.

maxlength : Int -> Attribute msg

Defines the maximum number of characters allowed in an input or textarea.

minlength : Int -> Attribute msg

Defines the minimum number of characters allowed in an input or textarea.

method : String -> Attribute msg

Defines which HTTP method to use when submitting a form. Can be GET (default) or POST.

multiple : Bool -> Attribute msg

Indicates whether multiple values can be entered in an input of type email or file. Can also indicate that you can select many options.

name : String -> Attribute msg

Name of the element. For example used by the server to identify the fields in form submits. For button, form, fieldset, iframe, input, object, output, select, textarea, map, meta, and param.

novalidate : Bool -> Attribute msg

This attribute indicates that a form shouldn't be validated when submitted.

pattern : String -> Attribute msg

Defines a regular expression which an input's value will be validated against.

readonly : Bool -> Attribute msg

Indicates whether an input or textarea can be edited.

required : Bool -> Attribute msg

Indicates whether this element is required to fill out or not. For input, select, and textarea.

size : Int -> Attribute msg

For input specifies the width of an input in characters.

For select specifies the number of visible options in a drop-down list.

for : String -> Attribute msg

The element ID described by this label or the element IDs that are used for an output.

form : String -> Attribute msg

Indicates the element ID of the form that owns this particular button, fieldset, input, label, meter, object, output, progress, select, or textarea.

Input Ranges

max : String -> Attribute msg

Indicates the maximum value allowed. When using an input of type number or date, the max value must be a number or date. For input, meter, and progress.

min : String -> Attribute msg

Indicates the minimum value allowed. When using an input of type number or date, the min value must be a number or date. For input and meter.

step : String -> Attribute msg

Add a step size to an input. Use step "any" to allow any floating-point number to be used in the input.

Input Text Areas

cols : Int -> Attribute msg

Defines the number of columns in a textarea.

rows : Int -> Attribute msg

Defines the number of rows in a textarea.

wrap : String -> Attribute msg

Indicates whether the text should be wrapped in a textarea. Possible values are "hard" and "soft".

Links and Areas

href : String -> Attribute msg

The URL of a linked resource, such as a, area, base, or link.

target : String -> Attribute msg

Specify where the results of clicking an a, area, base, or form should appear. Possible special values include:

  • _blank — a new window or tab
  • _self — the same frame (this is default)
  • _parent — the parent frame
  • _top — the full body of the window

You can also give the name of any frame you have created.

download : String -> Attribute msg

Indicates that clicking an a and area will download the resource directly. The String argument determins the name of the downloaded file. Say the file you are serving is named hats.json.

download ""               -- hats.json
download "my-hats.json"   -- my-hats.json
download "snakes.json"    -- snakes.json

The empty String says to just name it whatever it was called on the server.

hreflang : String -> Attribute msg

Two-letter language code of the linked resource of an a, area, or link.

media : String -> Attribute msg

Specifies a hint of the target media of a a, area, link, source, or style.

ping : String -> Attribute msg

Specify a URL to send a short POST request to when the user clicks on an a or area. Useful for monitoring and tracking.

rel : String -> Attribute msg

Specifies the relationship of the target object to the link object. For a, area, link.

Maps

ismap : Bool -> Attribute msg

When an img is a descendant of an a tag, the ismap attribute indicates that the click location should be added to the parent a's href as a query string.

usemap : String -> Attribute msg

Specify the hash name reference of a map that should be used for an img or object. A hash name reference is a hash symbol followed by the element's name or id. E.g. "#planet-map".

shape : String -> Attribute msg

Declare the shape of the clickable area in an a or area. Valid values include: default, rect, circle, poly. This attribute can be paired with coords to create more particular shapes.

coords : String -> Attribute msg

A set of values specifying the coordinates of the hot-spot region in an area. Needs to be paired with a shape attribute to be meaningful.

Embedded Content

src : String -> Attribute msg

The URL of the embeddable content. For audio, embed, iframe, img, input, script, source, track, and video.

height : Int -> Attribute msg

Declare the height of a canvas, embed, iframe, img, input, object, or video.

width : Int -> Attribute msg

Declare the width of a canvas, embed, iframe, img, input, object, or video.

alt : String -> Attribute msg

Alternative text in case an image can't be displayed. Works with img, area, and input.

Audio and Video

autoplay : Bool -> Attribute msg

The audio or video should play as soon as possible.

controls : Bool -> Attribute msg

Indicates whether the browser should show playback controls for the audio or video.

loop : Bool -> Attribute msg

Indicates whether the audio or video should start playing from the start when it's finished.

preload : String -> Attribute msg

Control how much of an audio or video resource should be preloaded.

poster : String -> Attribute msg

A URL indicating a poster frame to show until the user plays or seeks the video.

default : Bool -> Attribute msg

Indicates that the track should be enabled unless the user's preferences indicate something different.

kind : String -> Attribute msg

Specifies the kind of text track.

srclang : String -> Attribute msg

A two letter language code indicating the language of the track text data.

iframes

sandbox : String -> Attribute msg

A space separated list of security restrictions you'd like to lift for an iframe.

srcdoc : String -> Attribute msg

An HTML document that will be displayed as the body of an iframe. It will override the content of the src attribute if it has been specified.

Ordered Lists

reversed : Bool -> Attribute msg

Indicates whether an ordered list ol should be displayed in a descending order instead of a ascending.

start : Int -> Attribute msg

Defines the first number of an ordered list if you want it to be something besides 1.

Tables

align : String -> Attribute msg

Specifies the horizontal alignment of a caption, col, colgroup, hr, iframe, img, table, tbody, td, tfoot, th, thead, or tr.

colspan : Int -> Attribute msg

The colspan attribute defines the number of columns a cell should span. For td and th.

rowspan : Int -> Attribute msg

Defines the number of rows a table cell should span over. For td and th.

headers : String -> Attribute msg

A space separated list of element IDs indicating which th elements are headers for this cell. For td and th.

scope : String -> Attribute msg

Specifies the scope of a header cell th. Possible values are: col, row, colgroup, rowgroup.

Less Common Global Attributes

Attributes that can be attached to any HTML tag but are less commonly used.

accesskey : Char -> Attribute msg

Defines a keyboard shortcut to activate or add focus to the element.

contenteditable : Bool -> Attribute msg

Indicates whether the element's content is editable.

contextmenu : String -> Attribute msg

Defines the ID of a menu element which will serve as the element's context menu.

dir : String -> Attribute msg

Defines the text direction. Allowed values are ltr (Left-To-Right) or rtl (Right-To-Left).

draggable : String -> Attribute msg

Defines whether the element can be dragged.

dropzone : String -> Attribute msg

Indicates that the element accept the dropping of content on it.

itemprop : String -> Attribute msg
lang : String -> Attribute msg

Defines the language used in the element.

spellcheck : Bool -> Attribute msg

Indicates whether spell checking is allowed for the element.

tabindex : Int -> Attribute msg

Overrides the browser's default tab order and follows the one specified instead.

Miscellaneous

cite : String -> Attribute msg

Contains a URI which points to the source of the quote or change in a blockquote, del, ins, or q.

datetime : String -> Attribute msg

Indicates the date and time associated with the element. For del, ins, time.

pubdate : String -> Attribute msg

Indicates whether this date and time is the date of the nearest article ancestor element. For time.

manifest : String -> Attribute msg

Specifies the URL of the cache manifest for an html tag.