JAVASCRIPT

javascript add data to form

<input type="text" id="example">
<input type="submit" value="Submit" onclick="document.getElementById('example').setAttribute('value','My default value')">

how to append data to a form data in javascript

formData.append('username', 'Chris');
formData.append('userpic', myFileInput.files[0], 'chris.jpg');

how to append data to a form data in javascript

formData.append(name, value);
formData.append(name, value, filename);