2D array from C# to Javascript

Question 1

You can create a c# function and called it from client side. the same code you will have to write in GetData function and that will return string as you have serialize using JavaScriptSerializer.

var Json = <%= GetData(); %>

That will render page like this,

var Json = [["1","John","xyz","12000"],["2","Mike","pqr","15000"],["3","Nick","fjdu","18000"],["4","Brad","wee","22000"]]

And you can access values like Json[0][0] would return 1.

Code behind

public partial class Somepage : System.Web.UI.Page
{
    public string GetData()
    {
        SqlConnection con = new SqlConnection("Data Source=COMP7;Initial Catalog=GK_Practice;User ID=sa;Password=SQLEXPRESS");
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = con;
        cmd.CommandType = CommandType.Text;
        cmd.CommandText = "select * from employee";
        con.Open();

        SqlDataReader rd = cmd.ExecuteReader();

        int rowcount=0, columncount;

        while(rd.Read())
        {
            rowcount++;            
        }

        columncount = rd.FieldCount;
        rd.Close();
        rd = cmd.ExecuteReader();

        string[][] str=new string[rowcount][];
        int i = 0;
        while(rd.Read())
        {
           str[i] = new string[columncount];
           for (int j = 0; j < columncount; j++)
           {
               str[i][j] = rd.GetValue(j).ToString();
           }
           i++;
        }

        Label2.Text = str[1][1].ToString();
        JavaScriptSerializer js = new JavaScriptSerializer();
        string json = js.Serialize((object)str);
        rd.Close();
        con.Close();

        return json;
    }

    protected void Page_Load(object sender, EventArgs e)
    {
        // Just to feel you this is code behind
    }
}

Clint side (Javascript)

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <script type="text/javascript">

        var Json = <%= GetData(); %>

    </script>
</head>

Question 2

try this

var sb = new StringBuilder();
    sb.Append("<script>");
    sb.Append(string.Format("var jsonObj ={0}", json));
    sb.Append("</script>");
    ClientScript.RegisterStartupScript(this.GetType(), "jsonObjVar", sb.ToString());

then in your dom you will have the global variable name jsonObj.

Question 3

Depending you are using MVC razor or ASP, the syntax will change a bit on view. Using MVC razor you simply has to put the string into model variable (into controller) and access into the page.

var json = @model.MyString;