Notice that the binding is to the `disabled` property of the button's DOM element, not the attribute.
Data binding works with properties of DOM elements, components, and directives, not HTML attributes.
{@a html-attribute-vs-dom-property}
### HTML attributes and DOM properties
Angular binding distinguishes between HTML attributes and DOM properties.
Attributes initialize DOM properties and you can configure them to modify an element's behavior.
Properties are features of DOM nodes.
* A few HTML attributes have 1:1 mapping to properties; for example, `id`.
* Some HTML attributes don't have corresponding properties; for example, `aria-*`.
* Some DOM properties don't have corresponding attributes; for example, `textContent`.
<divclass="alert is-important">
Remember that HTML attributes and DOM properties are different things, even when they have the same name.
</div>
In Angular, the only role of HTML attributes is to initialize element and directive state.
When you write a data binding, you're dealing exclusively with the DOM properties and events of the target object.
#### Example 1: an `<input>`
When the browser renders `<input type="text" value="Sarah">`, it creates a
corresponding DOM node with a `value` property and initializes that `value` to "Sarah".
```html
<inputtype="text"value="Sarah">
```
When the user enters `Sally` into the `<input>`, the DOM element `value` property becomes `Sally`.
However, if you look at the HTML attribute `value` using `input.getAttribute('value')`, you can see that the attribute remains unchanged—it returns "Sarah".
The HTML attribute `value` specifies the initial value; the DOM `value` property is the current value.
To see attributes versus DOM properties in a functioning app, see the <live-examplename="binding-syntax"></live-example> especially for binding syntax.
#### Example 2: a disabled button
A button's `disabled` property is `false` by default so the button is enabled.
When you add the `disabled` attribute, you are initializing the button's `disabled` property to `true` which disables the button.
```html
<buttondisabled>Test Button</button>
```
Adding and removing the `disabled` attribute disables and enables the button.
However, the value of the attribute is irrelevant, which is why you cannot enable a button by writing `<button disabled="false">Still Disabled</button>`.
To control the state of the button, set the `disabled` property instead.
Property and attribute comparison
Though you could technically set the `[attr.disabled]` attribute binding, the values are different in that the property binding must be a boolean value, while its corresponding attribute binding relies on whether the value is `null` or not.
