var Form = React.createClass({

  firstMethod(e) {

    const re = /[0-9A-F:]+/g;

    if (!re.test(e.key)) {

      e.preventDefault();

    }

  },

​

  secondMethod(e) {

    const re = /[0-9A-F]+/g;

    if (!re.test(e.key)) {

      e.preventDefault();

    }

  },

  thirdMethod(e) {

    const re = /[0-9a-fA-F]+/g;

    if (!re.test(e.key)) {

      e.preventDefault();

    }

  },

​

  fourthMethod(e) {

    const re = /[a-fA-F]+/g;

    if (!re.test(e.key)) {

      e.preventDefault();

    }

  },

​

  render() {

    return (

      <form>

        <input ref="first" onKeyPress={(e) => this.firstMethod(e)} />

        <input ref="second" onKeyPress={(e) => this.secondMethod(e)} />

        <input ref="third" onKeyPress={(e) => this.thirdMethod(e)} />

        <input ref="fourth" onKeyPress={(e) => this.fourthMethod(e)} />

      </form>

    );

  }

});

​

ReactDOM.render(

  <Form />,

  document.getElementById('example')

);