title: Ensure that input value is string of alphabets in reactjs
body: <p>I'm developing a reactjs application and I want that my user must enter only alphabets in an input field.
  Here is my code.</p>
  <pre><code>&lt;input value= {this.state.val} onChange = {this.handleVal}/&gt;
  
  
  handleVal = (e)=&gt;{
        this.setState({
        val:e.target.value
        })
  }
  
  
  state = {
    val:''
  }
  </code></pre>
  <p>My component has lot of code but i entered only the relevant.
  Thanks in advance.</p>