function WhatIsOn()
            {
                if (document.getElementById("what_it_is_on") != null)
                {
                    document.getElementById("what_it_is_on").id = "what_it_is_on";
                    document.getElementById("how_to_use_it").id = "how_to_use_it";
                }
                else
                {
                    document.getElementById("what_it_is").id = "what_it_is_on";
                    document.getElementById("how_to_use_it_on").id = "how_to_use_it";
                }
                document.getElementById("what_it_is_content").style.display = "block";
                document.getElementById("how_to_use_content").style.display = "none";
            }
            function HowToUseOn()
            {
                if (document.getElementById("how_to_use_it") != null)
                {
                    document.getElementById("what_it_is_on").id = "what_it_is";
                    document.getElementById("how_to_use_it").id = "how_to_use_it_on";
                }
                else{
                    document.getElementById("what_it_is").id = "what_it_is";
                    document.getElementById("how_to_use_it_on").id = "how_to_use_it_on";
                }
                document.getElementById("what_it_is_content").style.display = "none";
                document.getElementById("how_to_use_content").style.display = "block";
            }