Button Examples and Reference

Button Basic Example

An example of a default button without any extra properties and n_clicks in the callback. n_clicks is an integer that represents that number of times the button has been clicked. Note that the original value is None.

import dash
import dash_html_components as html
import dash_core_components as dcc

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

app.layout = html.Div([
    html.Div(dcc.Input(id='input-on-submit', type='text')),
    html.Button('Submit', id='submit-val', n_clicks=0),
    html.Div(id='container-button-basic',
             children='Enter a value and press submit')
])


@app.callback(
    dash.dependencies.Output('container-button-basic', 'children'),
    [dash.dependencies.Input('submit-val', 'n_clicks')],
    [dash.dependencies.State('input-on-submit', 'value')])
def update_output(n_clicks, value):
    return 'The input value was "{}" and the button has been clicked {} times'.format(
        value,
        n_clicks
    )


if __name__ == '__main__':
    app.run_server(debug=True)
Enter a value and press submit

Determining which Button Changed with callback_context

This example utilizes the dash.callback_context property, to determine which input was changed.

# -*- coding: utf-8 -*-
import dash
from dash.dependencies import Input, Output
import dash_html_components as html

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

app.layout = html.Div([
    html.Button('Button 1', id='btn-nclicks-1', n_clicks=0),
    html.Button('Button 2', id='btn-nclicks-2', n_clicks=0),
    html.Button('Button 3', id='btn-nclicks-3', n_clicks=0),
    html.Div(id='container-button-timestamp')
])

@app.callback(Output('container-button-timestamp', 'children'),
              [Input('btn-nclicks-1', 'n_clicks'),
               Input('btn-nclicks-2', 'n_clicks'),
               Input('btn-nclicks-3', 'n_clicks')])
def displayClick(btn1, btn2, btn3):
    changed_id = [p['prop_id'] for p in dash.callback_context.triggered][0]
    if 'btn-nclicks-1' in changed_id:
        msg = 'Button 1 was most recently clicked'
    elif 'btn-nclicks-2' in changed_id:
        msg = 'Button 2 was most recently clicked'
    elif 'btn-nclicks-3' in changed_id:
        msg = 'Button 3 was most recently clicked'
    else:
        msg = 'None of the buttons have been clicked yet'
    return html.Div(msg)

if __name__ == '__main__':
    app.run_server(debug=True)

Button Properties

Access this documentation in your Python terminal with:
```python

help(dash_html_components.Button)
```

Our recommended IDE for writing Dash apps is Dash Enterprise’s
Data Science Workspaces,
which has typeahead support for Dash Component Properties.
Find out if your company is using
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.

children (a list of or a singular dash component, string or number; optional): The children of this component

aria-* (string; optional): A wildcard aria attribute

autoFocus (a value equal to: ‘autoFocus’, ‘autofocus’, ‘AUTOFOCUS’ | boolean; optional): The element should be automatically focused after the page loaded.

accessKey (string; optional): Keyboard shortcut to activate or add focus to the element.

className (string; optional): Often used with CSS to style elements with common properties.

contentEditable (string; optional): Indicates whether the element’s content is editable.

contextMenu (string; optional): Defines the ID of a <menu> element which will serve as the element’s context menu.

data-* (string; optional): A wildcard data attribute

disabled (a value equal to: ‘disabled’, ‘DISABLED’ | boolean; optional): Indicates whether the user can interact with the element.

dir (string; optional): Defines the text direction. Allowed values are ltr (Left-To-Right) or rtl (Right-To-Left)

draggable (string; optional): Defines whether the element can be dragged.

form (string; optional): Indicates the form that is the owner of the element.

formAction (string; optional): Indicates the action of the element, overriding the action defined in the <form>.

formEncType (string; optional): If the button/input is a submit button (type=”submit”), this attribute sets the encoding type to use during form submission. If this attribute is specified, it overrides the enctype attribute of the button’s form owner.

formMethod (string; optional): If the button/input is a submit button (type=”submit”), this attribute sets the submission method to use during form submission (GET, POST, etc.). If this attribute is specified, it overrides the method attribute of the button’s form owner.

formNoValidate (a value equal to: ‘formNoValidate’, ‘formnovalidate’, ‘FORMNOVALIDATE’ | boolean; optional): If the button/input is a submit button (type=”submit”), this boolean attribute specifies that the form is not to be validated when it is submitted. If this attribute is specified, it overrides the novalidate attribute of the button’s form owner.

formTarget (string; optional): If the button/input is a submit button (type=”submit”), this attribute specifies the browsing context (for example, tab, window, or inline frame) in which to display the response that is received after submitting the form. If this attribute is specified, it overrides the target attribute of the button’s form owner.

hidden (a value equal to: ‘hidden’, ‘HIDDEN’ | boolean; optional): Prevents rendering of given element, while keeping child elements, e.g. script elements, active.

id (string; optional): The ID of this component, used to identify dash components in callbacks. The ID needs to be unique across all of the components in an app.

key (string; optional): A unique identifier for the component, used to improve performance by React.js while rendering components See https://reactjs.org/docs/lists-and-keys.html for more info

lang (string; optional): Defines the language used in the element.

loading_state (dict; optional): Object that holds the loading state object coming from dash-renderer. loading_state has the following type: dict containing keys ‘is_loading’, ‘prop_name’, ‘component_name’. Those keys have the following types:

  • is_loading (boolean; optional): Determines if the component is loading or not
  • prop_name (string; optional): Holds which property is loading
  • component_name (string; optional): Holds the name of the component that is loading

n_clicks (number; default 0): An integer that represents the number of times that this element has been clicked on.

n_clicks_timestamp (number; default -1): An integer that represents the time (in ms since 1970) at which n_clicks changed. This can be used to tell which button was changed most recently.

name (string; optional): Name of the element. For example used by the server to identify the fields in form submits.

role (string; optional): The ARIA role attribute

spellCheck (string; optional): Indicates whether spell checking is allowed for the element.

style (dict; optional): Defines CSS styles which will override styles previously set.

type (string; optional): Defines the type of the element.

tabIndex (string; optional): Overrides the browser’s default tab order and follows the one specified instead.

title (string; optional): Text to be displayed in a tooltip when hovering over the element.

value (string; optional): Defines a default value which will be displayed in the element on page load.