这个JQuery AJAX代码有什么问题

Question

I was facing some problem with AJAX code. I was using MVC3 for our project. My requirement is bind the dropdown value using AJAX when page load. What happens when loading the page, the AJAX request send to the controller properly and return back to the AJAX function and binds the exact values in dropdown. But sometimes (When page refreshed or first time load) its not binding retrieved value. Rather its showing default value. Pls see my code and suggest me where i am doing wrong.

Edit: Even i tried to use async property to false. Its not at all send to the controller action method for getting the data.

Code

$.ajax({
            type: "POST",
            contentType: "application/json; charset=utf-8",
            url: '@Url.Action("GetUser", "Invoices")',
            data: "{'id':" + JSON.stringify(currval) + "}",
            dataType: "json",
            async: true,
            success: function (data) {
                $("#User-" + curr).select2("data", { id: data.Value, Name: data.Text });
                $(this).val(data.Value);
            }
        });

Thanks,

Answer 1

You are declaring your data property incorrectly. Try this:

data: { id: currval },

Answer 2

Let's say your Action method is below

public JsonResult hello(int id)
{
    return Json(new { Success = true }, JsonRequestBehavior.AllowGet);
}

and JQuery should be like below

<script language="javascript" type="text/javascript">
    $(document).ready(function () {
        var currval = 2;
        $.ajax({
            url: 'URl',
            async: true,
            type: 'POST',
            contentType: 'application/json; charset=utf-8',
            data: JSON.stringify({ id: currval }),
            success: function (data) {
            }
        });
    });
</script>