axios/docs/pages/advanced/html-form-processing.md

HTML form posting (browser)

You can also post a form directly from a HTML form element. This is useful when you have a form in your page and you want to submit it without any JavaScript code.

await axios.postForm('https://httpbin.org/post', document.querySelector('#htmlForm'));

FormData and HTMLForm objects can also be posted as JSON by explicitly setting the Content-Type header to application/json:

await axios.post('https://httpbin.org/post', document.querySelector('#htmlForm'), {
  headers: {
    'Content-Type': 'application/json',
  },
});

An example of a form that is valid and can be submitted by the above code is:

<form id="htmlForm">
  <input type="text" name="foo" value="1" />
  <input type="text" name="deep.prop" value="2" />
  <input type="text" name="deep prop spaced" value="3" />
  <input type="text" name="baz" value="4" />
  <input type="text" name="baz" value="5" />

  <select name="user.age">
    <option value="value1">Value 1</option>
    <option value="value2" selected>Value 2</option>
    <option value="value3">Value 3</option>
  </select>

  <input type="submit" value="Save" />
</form>

The above form will be submitted as:

{
  "foo": "1",
  "deep": {
    "prop": {
      "spaced": "3"
    }
  },
  "baz": ["4", "5"],
  "user": {
    "age": "value2"
  }
}

::: tip Path collisions overwrite earlier values Field names are parsed into property paths by splitting on ., brackets, or whitespace. Two inputs whose paths overlap will collide: in the example above, deep.prop parses to ["deep", "prop"] and deep prop spaced parses to ["deep", "prop", "spaced"], so the deeper assignment replaces deep.prop = "2" with the nested object { spaced: "3" }. Pick non-overlapping field names if you need both values. :::

::: warning Sending Blobs/Files as JSON (base64) is not currently supported. :::