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Just click f12 in your browser, find the submit button in the html, and then remove the disabled ! It will submit the form even if the inputs are empty.
The main thing you need is a template variable, in my case it is #register="ngForm" , and you will use it for validating the form at the submit button, by setting its value to disabled attribute like [disabled]="!
By default a button's state is enabled in HTML so by setting disabled = true, we have disabled the button for the user. 3. Then we add an event handler (addEventListener) to the input field with the event property change which monitors the interaction with elements.
You'll need to keep the current value of the input in state (or pass changes in its value up to a parent via a callback function, or sideways, or <your app's state management solution here> such that it eventually gets passed back into your component as a prop) so you can derive the disabled prop for the button.
Example using state:
<meta charset="UTF-8">
<script src="https://fb.me/react-0.13.3.js"></script>
<script src="https://fb.me/JSXTransformer-0.13.3.js"></script>
<div id="app"></div>
<script type="text/jsx;harmony=true">void function() { "use strict";
var App = React.createClass({
getInitialState() {
return {email: ''}
},
handleChange(e) {
this.setState({email: e.target.value})
},
render() {
return <div>
<input name="email" value={this.state.email} onChange={this.handleChange}/>
<button type="button" disabled={!this.state.email}>Button</button>
</div>
}
})
React.render(<App/>, document.getElementById('app'))
}()</script>Using constants allows to combine multiple fields for verification:
class LoginFrm extends React.Component {
constructor() {
super();
this.state = {
email: '',
password: '',
};
}
handleEmailChange = (evt) => {
this.setState({ email: evt.target.value });
}
handlePasswordChange = (evt) => {
this.setState({ password: evt.target.value });
}
handleSubmit = () => {
const { email, password } = this.state;
alert(`Welcome ${email} password: ${password}`);
}
render() {
const { email, password } = this.state;
const enabled =
email.length > 0 &&
password.length > 0;
return (
<form onSubmit={this.handleSubmit}>
<input
type="text"
placeholder="Email"
value={this.state.email}
onChange={this.handleEmailChange}
/>
<input
type="password"
placeholder="Password"
value={this.state.password}
onChange={this.handlePasswordChange}
/>
<button disabled={!enabled}>Login</button>
</form>
)
}
}
ReactDOM.render(<LoginFrm />, document.body);<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<body>
</body>Another way to check is to inline the function, so that the condition will be checked on every render (every props and state change)
const isDisabled = () =>
// condition check
This works:
<button
type="button"
disabled={this.isDisabled()}
>
Let Me In
</button>
but this will not work:
<button
type="button"
disabled={this.isDisabled}
>
Let Me In
</button>
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