[](https://www.npmjs.com/package/@polymer/iron-validatable-behavior) [](https://travis-ci.org/PolymerElements/iron-validatable-behavior) [](https://webcomponents.org/element/@polymer/iron-validatable-behavior) ## IronValidatableBehavior Use `IronValidatableBehavior` to implement an element that validates user input. By using this behaviour, your custom element will get a public `validate()` method, which will return the validity of the element, and a corresponding `invalid` attribute, which can be used for styling. Can be used alongside an element implementing the `IronValidatableBehavior` behaviour. See: [Documentation](https://www.webcomponents.org/element/@polymer/iron-validatable-behavior), [Demo](https://www.webcomponents.org/element/@polymer/iron-validatable-behavior/demo/demo/index.html). ## Usage ### Installation ``` npm install --save @polymer/iron-validatable-behavior ``` ### In a Polymer 3 element ```js import {PolymerElement, html} from '@polymer/polymer'; import {mixinBehaviors} from '@polymer/polymer/lib/legacy/class.js'; import {IronValidatableBehavior} from '@polymer/iron-validatable-behavior/iron-validatable-behavior.js'; class SampleElement extends mixinBehaviors([IronValidatableBehavior], PolymerElement) { static get template() { return html` `; // Override this method if you want to implement custom validity // for your element. This element is only valid if the value in the // input is "cat". function _getValidity() { return this.$.input.value === 'cat'; } } } customElements.define('sample-element', SampleElement); ``` ### In an html file using the element ```html Validate! ``` ## Contributing If you want to send a PR to this element, here are the instructions for running the tests and demo locally: ### Installation ```sh git clone https://github.com/PolymerElements/iron-validatable-behavior cd iron-validatable-behavior npm install npm install -g polymer-cli ``` ### Running the demo locally ```sh polymer serve --npm open http://127.0.0.1:/demo/ ``` ### Running the tests ```sh polymer test --npm ```