Issue with Updating Model in Razor View

Question

first post. Trying so solve an issue I am seeing here between my Razor view and model. I have a popup window that is being fed a partial view and model.

 public IActionResult ClickedCovid19Question(int id)
    {
        var existingQ = db.CustomerInfoItems.Find(id);

        var suffix = existingQ.Suffix;

        if (suffix.Length == 2)
            suffix = suffix.Insert(0, "0");

        var salesman = SalesmanHelper.GetSalesmanNum();

        var par = db.Pars.Where(p => p.AccountNo == existingQ.CustNum).Where(p => p.Suffix == suffix)
                    .Where(p => p.SalesmanNumber == salesman).FirstOrDefault();
        var clickedCovid19Model = new ClickedCovidQuestionModel
        { //insert model data here }
        
        clickedCovid19Model.Machines = db.MachinePopulationItems
            .Where(m => m.CustNum == existingQ.CustNum)
            .ToList();

        return View("~/Views/Covid19/_ClickedCovid19Question.cshtml", clickedCovid19Model);
    }

This works great on the first page render. I see the data fill my UI elements that are called from the @model on the razor page. When my user updates a field here and submits, I use this function

function SaveClickedCovid19Question(idJS) {
    C19ParChanged('@Model.Par');
    var jsonJS = SerializeForm("#c19QuestionForm");

    $.ajax({
        url: '/Covid19/SaveClickedCovid19Question',
        type: 'GET',
        data:
        {
            id: idJS,
            json: jsonJS
        },
        success: function (data) {
            Alert(data);
            RefreshLV("CovidQuestions");
            HideWindow("#Covid19Question");
        },
        error: function (data, error, e2) {
            debugger;
        }
    });
}

However, after the popup window is closed, and another popup is opened, we call that same ClickedCovid19Question IActionResult to populate our form again. It populates the UI fine with the new model it generated, debugging shows it creates a new model with all the correct data. The issue arrises when a user submits this form again, the model on the Razor view seems to think it is still the model of the very first submission. An example of this is the first line of the javascript function. When the razor view was created, it had the correct @Model.Par data, as I could see when I created a few elements to display it. However, when trying to capture that data using @Model.Par, it captures the original Model.Par data. Long story short, subsequent popups don't overwrite the Model data from the very first one. I am stumped, because this system works in so many other areas of our codebase. I can fix this buy creating hidden elements that will store the data I need to send in any requests, but I feel like there has to be a better answer than that.

Edit: Below is an example I was using to test. The view part below will always display the correct par data in the id=parID input box. However, on the second popup and everytime after, if I was to run the simple javascript function below to find the data held by model, it will ALWAYS update to the data from the first model the page ever rendered, which seems inconsistent with other areas of my code that do work normally.

function updateParID() {
        $("#c19QuestionForm").find("#parID").val('@Model.Par');

    }


<input id="parID" type="text" disabled="disabled" value="@Model.Par"/>
        <partial name="Forms/_FormDropDown" model=@(new FormDropDownModel { Name = "Par", Values = Lists.ParStates(), Value = Model.CallsPerYear}) />
        <button type="submit" onclick="RefreshWindow('@Model.ID')">Refresh</button>
        <button type="submit" onclick="updateParID()">Update Par ID</button>

Answer 1

So, I actually ended up solving this. My issue was, trying to bind the data from the @Model.Par or any model data INSIDE a javascript function will ALWAYS bind using the initial model. Every subsequent call to this function will ALWAYS only use that very first model. My solution that I overlooked was to actually send the data to the function from the model as a parameter first, and not try to bind it inside the javascript function.

Example: My edit has these lines

function updateParID() {
        $("#c19QuestionForm").find("#parID").val('@Model.Par');

    }

<button type="submit" onclick="updateParID()">Update Par ID</button>

When I change the order of how I capture that model to this:

function updateParID(parID) {
        $("#c19QuestionForm").find("#parID").val(parID);

    }

<button type="submit" onclick="updateParID('@Model.Par')">Update Par ID</button>

This now correctly captures the model data that is present. I am sure there is some reason javascript works this way, but it is unknown to me, if anyone can shed light on it. Forgive me if it is a simple answer, I am new to web programming. Thank you all for helping out!