I have make my existing method to static method to get access in javascript, like..

 [WebMethod(EnableSession = true), ScriptMethod()]
public static void Build(String ID)
{
    Control releaseControl = LoadControl("~/Controls/MyControl.ascx");
    //An Object reference is required for the non-static field, mthod or property
    // 'System.Web.UI.TemplateControl.LoadControl(string)'
    plc.Controls.Add(releaseControl); // where plc is place holder control
    //object reference is required for the nonstatic field, method, or property '_Default.pl'
}

When I build I am getting error and I have posted these in comments below each line

before converted it to static method, it working perfectly.

Please suggest me the solution of my issue.

Thanks