getting error on passing string as json object in ajax jquery

Question

I'm trying to pass a string in code behind method using ajax jquery but getting a stupid error. If I pass integer only then it works fine but in case of string it's not working this is what i've tried csharp code

public static string GetQuickVD(string key)
{
    return key.ToString();
}

jquery

$(document).ready(function () {
     GetQuickVL();
});
function GetQuickVL() {
     var Nid = new Array();
     for (var key in localStorage) {
         if (key.substring(0, 4) == "vhs-") {
             Nid += key.replace('vhs-', '') + ",";
         }
     }
     $.ajax({
         type: "POST",
         url: "QuickViewList.aspx/GetQuickVD",
         data: '{key: ' +'345,' + '}',
         contentType: "application/json; charset=utf-8",
         dataType: "json",
         success: OnSuccess,
         failure: function (response) {
              alert(response.response);
         },
         error: function (response) {
              alert(response.error);
         }
      });
}
function OnSuccess(response) {
      alert(response.d);
}

Answer 1

use like this

data: {key:  "345" }

You can also use like,

type: "GET",
url: "QuickViewList.aspx/GetQuickVD?key=355",

Edit

data: JSON.stringify({"key":  "345"}),