Reactjs：表单操作方法和onSubmit

Question

I have a situation where I need to submit my form. When I use this method 1

Method 1

<form action="my_redirect_url" method="post" onSubmit={this.registerEmail.bind(this)}>
   <input
     type="text"
     placeholder='Email address'
     name='EMAIL'
     value={this.state.email}
     onChange={this.handleChangeEmail}
   />
   <button type='submit' />
</form>

Then the form submits perfectly but I miss the form validation ie the email validation part. Its valid or not, the form redirects

Method 2

// onSubmit method
registerEmail = (e) => {
  e.preventDefault();
  let { email } = this.state;
  let emailValidated = validateEmail(email);
  if (emailValidated) {
    fetch('my_redirect_url', {
      method: 'post',
      body : JSON.stringify({
        EMAIL: email
      }),
      headers: {
        'Accept': 'application/json',
        'Content-Type': 'application/json'
      }
    })
    .then(ParseJSON) // It parses the output
    .catch(function(error) {
      console.log("error---", error)
    });
  } else {
    alert("invalid email")
  }
}

// Form
<form onSubmit={this.registerEmail.bind(this)}>
   <input
     type="text"
     placeholder='Email address'
     name='EMAIL'
     value={this.state.email}
     onChange={this.handleChangeEmail}
   />
   <button type='submit' />
</form>

In Method 2, the validation is done correctly but then it doesnot redirects and says an error that Fetch api cannot load 'my_redirect_url' Response for preflight is invalid (redirect)

So whats the issue and how can it be solved?

Answer 1

If you tell the program to e.preventDefault() , then he won't execute the normal redirect, which we are all waiting for.

So vice versa you have to remove it to redirect the user afterward. Only preventDefault() if the E-Mail is incorrect.