catapult/third_party/polymer/components/iron-input/README.md


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[![Build status](https://travis-ci.org/PolymerElements/iron-input.svg?branch=master)](https://travis-ci.org/PolymerElements/iron-input)

_[Demo and API docs](https://elements.polymer-project.org/elements/iron-input)_


## &lt;iron-input&gt;

`<iron-input>` adds two-way binding and custom validators using `Polymer.IronValidatorBehavior`
to `<input>`.

### Two-way binding

By default you can only get notified of changes to an `input`'s `value` due to user input:

```html
<input value="{{myValue::input}}">
```

`iron-input` adds the `bind-value` property that mirrors the `value` property, and can be used
for two-way data binding. `bind-value` will notify if it is changed either by user input or by script.

```html
<input is="iron-input" bind-value="{{myValue}}">
```

### Custom validators

You can use custom validators that implement `Polymer.IronValidatorBehavior` with `<iron-input>`.

```html
<input is="iron-input" validator="my-custom-validator">
```

### Stopping invalid input

It may be desirable to only allow users to enter certain characters. You can use the
`prevent-invalid-input` and `allowed-pattern` attributes together to accomplish this. This feature
is separate from validation, and `allowed-pattern` does not affect how the input is validated.

```html
<!-- only allow characters that match [0-9] -->
<input is="iron-input" prevent-invalid-input allowed-pattern="[0-9]">
```