PowerButton CSS Styling

Smart.PowerButton represents a switch button that has three states: null, checked and unchecked. The state can be changed by clicking on the element or by setting the checked property to the desired state.

Required files

The Smart.PowerButton element requires the following file references to be placed on a web page in order for the custom element to be successfully registered and properly working:

  • smart.element.js -- this is the base file that defines the common architecture of all Smart custom elements. It is part of the repository ni-kismet/smart-element.
  • smart.powerbutton.js -- this file defines the functionality of the Smart.PowerButton custom element.

Smart.PowerButton also requires the following style sheets in order to be displayed correctly.

  • smart.base.css -- the base style sheet file.


To create an instance of the Smart.PowerButton custom element, insert the following tag in an HTML page:


To set properties of the custom element initially, do so by setting the respective attributes of the tag, e.g.:

<smart-power-button checked></smart-power-button>

Getting and setting properties dynamically

Before accessing the custom element's API in JavaScript, the custom element's instance has to be retrieved:

let customElement = document.querySelector('smart-power-button');

Properties are represented as members of the custom element's instance object and can be accessed as such.

Here is an example showing how to get a property dynamically:

let customElement = customElement.checked;

Here is an example showing how to set a property dynamically:

customElement.checked = true;

Styling (CSS API)

Smart HTML Elements use a pair of css files - smart.base.css and smart.[theme name].css. The base stylesheet creates the styles related to the element's layout like margin, padding, border-width, position. The second CSS file applies the HTML Element's colors, fonts, borders and backgrounds. The smart.base.css should be included before the second CSS file.

CSS selectors

The following CSS selectors can be used to style Smart.PowerButton:

  • smart-power-button - the element itself. Can be used to set width and height for the whole element.
    • .smart-container - the container that holds all of the internals of the element. Shoudn't be used for styling.
    • .smart-animation - used for animation purposes.
    • .smart-input - an HTML Span element used to hold the power icon.
    • INPUT element - an HTML Input element used to include a value on form submit.

CSS variables

Smart.PowerButton uses the following CSS variables:

  • --smart-power-button-default-width - used to set the default width of the element. Default value is 30px.
  • --smart-power-button-default-height - used to set the default height of the element. Default value is 30px.