why does my page method does not work in firefox and safari?

function SendMail() {
      var user = document.getElementById('<%=UserName.ClientID %>');
      var val = user.value;

      var randomNumber = 12345;

        var nonRandomPassword = 23412;
        var toAddress = val;
        PageMethods.SendResetMailMessage(toAddress, randomNumber, nonRandomPassword, CloseWindow, OnFailed);

    }

    function CloseWindow(ret) {

      if (ret == "1") {
        alert(ret);
        var windowObj = window.self;
        windowObj.opener = window.self;
        windowObj.close();
      }
    }

    function OnFailed(error) {
      alert("Error in message");
    }