Loop through all GridView Rows and save data to database using jQuery AJAX in ASP.Net

Hello Everyone. I want to insert gridview data to database using Javascript and Ajax and I am almost done. But the main problem  is that only last row of gridview is going to the database.

Here is my Javascript code 

$(function () {
            $("[id*=btnSave]").bind("click", function () {
                var product = {};
                product.Item = $("[id*=gvDest] tr:last").find("td:nth-child(1)").html();
                product.Price = $("[id*=gvDest] tr:last").find("td:nth-child(2)").html();
                $.ajax({
                    type: "POST",
                    url: "Default.aspx/SaveProduct",
                    data: '{product: ' + JSON.stringify(product) + '}',
                    contentType: "application/json; charset=utf-8",
                    dataType: "json",

                    success: function (response) {
                        alert("Product has been added successfully.");

                    }
                });
                return false;
            });

        });

So my question is how can loop through gridview and fetch each row using javascript.

Please help.