session form submit

if you could share your code?

However here are some steps

aspx

JS Code 

function saveDetails() {
    // Code to display entered details (you can use alert or display in a div)
    document.getElementById('btnSubmit').style.display = 'none';
    document.getElementById('btnUpdate').style.display = 'inline';
    return false; // Prevents the form from submitting to the server
}

code-behind

protected void btnSubmit_Click(object sender, EventArgs e)
{
    // Save details to the database
    // You can access form fields using Request.Form["fieldName"]
    // Example: string studentName = Request.Form["txtStudentName"];

    // After saving, you might want to redirect the user or perform other actions
}

protected void btnUpdate_Click(object sender, EventArgs e)
{
    // Update details in the database
    // You can access form fields using Request.Form["fieldName"]
    // Example: string updatedStudentName = Request.Form["txtStudentName"];

    // After updating, you might want to redirect the user or perform other actions
}