Customizing a Component's Element

To use a tag other than div, subclass Component and assign it a tagName property. This property can be any valid HTML5 tag name as a string.

import Component from '@ember/component';

export default Component.extend({
  tagName: 'nav'
});

<ul>
  <li><LinkTo @route="home">Home</LinkTo></li>
  <li><LinkTo @route="about">About</LinkTo></li>
</ul>

You can specify the class of a component's element at invocation time the same way you would for a regular HTML element:

<NavigationBar class="primary" />

You can also specify which class names are applied to the component's element by setting its classNames property to an array of strings:

import Component from '@ember/component';

export default Component.extend({
  classNames: ['primary']
});

If you want class names to be determined by properties of the component, you can use class name bindings. If you bind to a Boolean property, the class name will be added or removed depending on the value:

import Component from '@ember/component';

export default Component.extend({
  classNameBindings: ['isUrgent'],
  isUrgent: true
});

This component would render the following:

<div class="ember-view is-urgent"></div>

If isUrgent is changed to false, then the is-urgent class name will be removed.

By default, the name of the Boolean property is dasherized. You can customize the class name applied by delimiting it with a colon:

import Component from '@ember/component';

export default Component.extend({
  classNameBindings: ['isUrgent:urgent'],
  isUrgent: true
});

This would render this HTML:

<div class="ember-view urgent">

Besides the custom class name for the value being true, you can also specify a class name which is used when the value is false:

import Component from '@ember/component';

export default Component.extend({
  classNameBindings: ['isEnabled:enabled:disabled'],
  isEnabled: false
});

This would render this HTML:

<div class="ember-view disabled">

You can also specify a class which should only be added when the property is false by declaring classNameBindings like this:

import Component from '@ember/component';

export default Component.extend({
  classNameBindings: ['isEnabled::disabled'],
  isEnabled: false
});

This would render this HTML:

<div class="ember-view disabled">

If the isEnabled property is set to true, no class name is added:

<div class="ember-view">

If the bound property's value is a string, that value will be added as a class name without modification:

import Component from '@ember/component';

export default Component.extend({
  classNameBindings: ['priority'],
  priority: 'highestPriority'
});

This would render this HTML:

<div class="ember-view highestPriority">

You can bind attributes to the DOM element that represents a component by using attributeBindings:

import Component from '@ember/component';

export default Component.extend({
  tagName: 'a',
  attributeBindings: ['href'],

  href: 'http://emberjs.com'
});

You can also bind these attributes to differently named properties:

import Component from '@ember/component';

export default Component.extend({
  tagName: 'a',
  attributeBindings: ['customHref:href'],

  customHref: 'http://emberjs.com'
});

If the attribute is null, it won't be rendered:

import Component from '@ember/component';

export default Component.extend({
  tagName: 'span',
  attributeBindings: ['title'],

  title: null,
});

This would render this HTML when no title is passed to the component:

<span class="ember-view">

...and this HTML when a title of "Ember JS" is passed to the component:

<span class="ember-view" title="Ember JS">