How to Pass data to controller using post method of javascript in laravel

I want pass data from View to Controller along with one variable indicating what I need to perform on controller

Here is code for view function addUpdateData(data)

{
    alert(data);
    $(function(){
      $.ajax({
        method : "POST",
        url: "welcome/addupdate",        
        data: {id: data},        
        success : function(response)
        {
          alert(response);
        }
      });
    });
}

<input type="submit" id="add" class="btn btn-primary" onclick="addUpdateData(id)" value="Add"></button>

Below is code for routes.php

Route::post('welcome/addupdate','FormController@addUpdateData');

Below is code for controller

public function addUpdateData(Request $req)
    {
        $id = $req['data'];
        return $id;
}

I want to receive posted data on controller with data variable where I will get whether I will add or update data..

I am getting error of Method Not Allowed I don't know what I am Missing!!!

please help

via Chebli Mohamed