CODE EXAMPLE FOR JAVASCRIPT

input type email react js-validation

    class Test extends React.Component {
        constructor(props){
           super(props);
      
           this.state = {
               fields: {},
               errors: {}
           }
        }
    
        handleValidation(){
            let fields = this.state.fields;
            let errors = {};
            let formIsValid = true;

            //Name
            if(!fields["name"]){
               formIsValid = false;
               errors["name"] = "Cannot be empty";
            }
      
            if(typeof fields["name"] !== "undefined"){
               if(!fields["name"].match(/^[a-zA-Z]+$/)){
                  formIsValid = false;
                  errors["name"] = "Only letters";
               }        
            }
       
            //Email
            if(!fields["email"]){
               formIsValid = false;
               errors["email"] = "Cannot be empty";
            }
      
            if(typeof fields["email"] !== "undefined"){
               let lastAtPos = fields["email"].lastIndexOf('@');
               let lastDotPos = fields["email"].lastIndexOf('.');

               if (!(lastAtPos < lastDotPos && lastAtPos > 0 && fields["email"].indexOf('@@') == -1 && lastDotPos > 2 && (fields["email"].length - lastDotPos) > 2)) {
                  formIsValid = false;
                  errors["email"] = "Email is not valid";
                }
           }  

           this.setState({errors: errors});
           return formIsValid;
       }
        
       contactSubmit(e){
            e.preventDefault();

            if(this.handleValidation()){
               alert("Form submitted");
            }else{
               alert("Form has errors.")
            }
      
        }
    
        handleChange(field, e){         
            let fields = this.state.fields;
            fields[field] = e.target.value;        
            this.setState({fields});
        }
    
        render(){
            return (
                <div>           
                   <form name="contactform" className="contactform" onSubmit= {this.contactSubmit.bind(this)}>
                        <div className="col-md-6">
                          <fieldset>
                               <input ref="name" type="text" size="30" placeholder="Name" onChange={this.handleChange.bind(this, "name")} value={this.state.fields["name"]}/>
                               <span style={{color: "red"}}>{this.state.errors["name"]}</span>
                              <br/>
                             <input refs="email" type="text" size="30" placeholder="Email" onChange={this.handleChange.bind(this, "email")} value={this.state.fields["email"]}/>
                             <span style={{color: "red"}}>{this.state.errors["email"]}</span>
                             <br/>
                             <input refs="phone" type="text" size="30" placeholder="Phone" onChange={this.handleChange.bind(this, "phone")} value={this.state.fields["phone"]}/>
                             <br/>
                             <input refs="address" type="text" size="30" placeholder="Address" onChange={this.handleChange.bind(this, "address")} value={this.state.fields["address"]}/>
                             <br/>
                         </fieldset>
                      </div>
          
                  </form>
                </div>
          )
        }
    }

    React.render(<Test />, document.getElementById('container'));