Q:

Calling a HTTP POST method in a MVC Controller from the View's Javascript & Database saving

I am trying to update a value in my database. When the user presses the update button this script is called.
View Code:
<script>
    function scr_UpdateQuote(field) {
        var r = confirm("Are you sure you want to update your quote?");
        if (r == true) {
            var textBox_UserTitle = document.getElementById(field);
            *CODE TO POST METHOD HERE*
        }
    }
</script>

In the controller, the value is then revived and saved into the database. A message is sent back to let the user know their quote was updated.
Controller Code:
[HttpGet]
public ActionResult UpdateQuote(string newQuote)
{

    *REPLACE QUOTE IN DATABASE*
    ViewBag.QuoteUpdated = "Your Quote has been updated.";

    return View();
}

I am having difficulty finding out how to write the code described between the **'s
(For the database part I have a user-id that can be used to identify the row)

A:

You can use form posting like this:
    $("#YourForm").submit(function() {
        $.post("/YourController/UpdateQuote", $("#YourForm").serialize())  
        //this will serialize your form into: 
        // newQuote=someValue&&someOtherVariable=someOtherValue etc.
        .done(function(data) {
            // do what ever you want with the server response
        });
    })

or you can use an ajax post:
    $.ajax({
            type: "POST",
            url: "/YourController/UpdateQuote",
            data: {newQuote: document.getElementById(field)},
            dataType: "json",
            success: function(data) {
                // do what ever you want with the server response
            },
            error: function(){
                // error handling
            }
        });

For using the data, assuming you have an DbContext called MyDbContext:
[HttpGet]
public ActionResult UpdateQuote(string newQuote)
{
    // get userID somehow, either from session, or pass as another parameter here
    using (var dc = new MyDbContext)
    {
       var quoteToUpdate = dc.QuotesTable.FirstOrDefault(q => q.UserID == userID)
       quoteToUpdate.quoteColumn = newQuote;
       dc.SaveChanges();
    }
    ViewBag.QuoteUpdated = "Your Quote has been updated.";

    return View();
}

