html form does not get sent after onSubmit function

问题

The geocodeAddress() function uses fetch to send a http request. Before I added "event.preventDefault()" as a parameter to the function, it would not run properly (TypeError: Network Error) as the request was being interrupted by the page reloading caused by the form being sent. However, once I added it, the form no longer gets sent. I don't think the problem lies with the php code as I have not altered it at all. What could be causing this?

I had the same error in this post before 'TypeError: NetworkError when attempting to fetch resource' on form submit ReactJS

    <form action="private/database.php" method="POST" onsubmit="geocodeAddress(event.preventDefault())"> 
      <input type="text" name="surname" placeholder="性氏" required><br>
      <input type="text" name="given_name" placeholder="名字" required><br>
      <label for="male">
        <input type="radio" id="male" name="gender" required>
        男性
      </label>
      <label for="female">
        <input type="radio" id="female" name="gender">
        女性
      </label><br>
      <input type="text" name="email" placeholder="電子信箱" required><br>
      <input type="text" name="phone_number" placeholder="電話" required><br>
      <input type="text" id="address" name="address" placeholder="地址" required><br>
      <input type="hidden" id="lat" name="lat">
      <input type="hidden" id="lng" name="lng">
      <input type="date" name="cleaning_date" required><br>
      <input type="submit" name="form_submit">
    </form>
    <script>
        function handleErrors(res) {
          if (!res.ok) {
            throw Error(res.statusText);
          }
          return res;
        }

        function geocodeAddress() {
          const address = document.getElementById('address').value;
          fetch(`https://maps.googleapis.com/maps/api/geocode/json?address=${address}&key=AIzaSyDxsdfWYv25UrruPXLqeXKVYUnD-VyReA`)
            .then(handleErrors)
            .then(res => res.json())
            .then(data => {
              console.log(data);
              document.getElementById('lat').value = data.results[0].geometry.location.lat.toString();
              document.getElementById('lng').value = data.results[0].geometry.location.lng.toString();
            })
            .catch(error => console.log(error));
        }
    </script>

回答1:

This is a pretty simple issue. event.preventDefault() stops the default action, that the event would do, which in this case is submitting the form. This means the fetch isn't interrupted, but of course, the form doesn't submit.

In order to fix this, you have to manually submit the form after the fetch has succeeded. This can be easily done by executing event.target.submit(). (event.target references the form, so we are simply calling the submit function of the form) Here is the modified geocodeAddress function, that should do just that:

function geocodeAddress(event) {
  event.preventDefault() // prevent the submit from happening immediately
  const address = document.getElementById('address').value;
  fetch(`https://maps.googleapis.com/maps/api/geocode/json?address=${address}&key=AIzaSyDxsdfWYv25UrruPXLqeXKVYUnD-VyReA`)
    .then(handleErrors)
    .then(res => res.json())
    .then(data => {
      console.log(data);
      document.getElementById('lat').value = data.results[0].geometry.location.lat.toString();
      document.getElementById('lng').value = data.results[0].geometry.location.lng.toString();
      event.target.submit() // trigger the submit again once the fetch has finished
    })
    .catch(error => console.log(error));
}

Oh and also, in the onsubmit of the form, you should just have the "geocodeAddress()".

<form action="private/database.php" method="POST" onsubmit="geocodeAddress()"> 

来源：https://stackoverflow.com/questions/65382736/html-form-does-not-get-sent-after-onsubmit-function