First you should add form as follows:
@using (Html.BeginForm("Your Action", "Your Controller", FormMethod.Post, new { enctype = "multipart/form-data", id = "Your FormId" }))
{
......
}
Then when you click save button, it should post the form as follows:
function save() {
var isValid = $("#Your FormId ").valid();
if (isValid) {
$("#Your FormId ").ajaxSubmit(function (result) {
......
});
}
}