In JavaScript, the FormData() object is primarily used to construct and send data as part of a form submission in an AJAX request. When using FormData() to submit a form with a specific enctype attribute, you don't need to set the enctype directly on the FormData object itself. Instead, you set the enctype on the form element that you use to collect the data into the FormData object.

Here's how you can do it:

  1. Create a <form> element in your HTML file:
<form id="myForm" enctype="multipart/form-data"> <!-- Your form fields go here --> <input type="text" name="field1" value="value1"> <input type="file" name="file1"> <!-- Add other form fields as needed --> </form>
  1. Use JavaScript to create a FormData object from the form element:
const myForm = document.getElementById('myForm'); const formData = new FormData(myForm);
  1. Now you have a formData object that contains the form data, and the enctype attribute is implicitly set to "multipart/form-data" because of the enctype attribute on the form element.

  2. You can then use this formData object to send the data in an AJAX request using fetch() or any other method you prefer.

fetch('/submit-form', { method: 'POST', body: formData, }) .then((response) => { // Handle the response }) .catch((error) => { // Handle errors });

When you use FormData() in this way, the enctype is automatically set based on the form's enctype attribute. You don't need to set it explicitly on the FormData object itself.

Remember that if you need to send files or other binary data, you should use the "multipart/form-data" enctype to ensure that the data is correctly encoded for the server to handle file uploads or other binary data submissions.

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