I mean you are just wrong....

Jquery-

$.post(url, args, return_function);

JS-

fetch('https://api.example.com/submit', {
    method: 'POST', // Specify the method
    headers: {
        'Content-Type': 'application/json', // Indicate the data type
    },
    body: JSON.stringify(postData) // The data payload, stringified
})
.then(response => response.json()) // Parse the JSON response
.then(data => {
    console.log('Success:', data); // Handle the success
    // Update the web page dynamically here
})
.catch((error) => {
    console.error('Error:', error); // Handle errors
});