function swap_selected(elem){

   if(elem){

      //return if you clicked the selected tab

      if(elem.className == "selected") return;



      var tab_1 = document.getElementById("T1");
      var tab_2 = document.getElementById("T2");
      var tab_3 = document.getElementById("T3");
      var tab_4 = document.getElementById("T4");
	  var tab_5 = document.getElementById("T5");
      
	  var content_1 = document.getElementById("C1");
      var content_2 = document.getElementById("C2");
      var content_3 = document.getElementById("C3");
      var content_4 = document.getElementById("C4");
	  var content_5 = document.getElementById("C5");


      if(elem == tab_1){

         tab_1.className = "selected";

         content_1.style.display = "block";



         tab_2.className = "";

         content_2.style.display = "none";
         
		 tab_3.className = "";

         content_3.style.display = "none";
         
		 tab_4.className = "";

         content_4.style.display = "none";
  
         tab_5.className = "";

         content_5.style.display = "none";
  
         }

         else if(elem == tab_2)
		 {

         tab_2.className = "selected";

         content_2.style.display = "block";



         tab_1.className = "";

         content_1.style.display = "none";
         
		 tab_3.className = "";

         content_3.style.display = "none";
        
         tab_4.className = "";

         content_4.style.display = "none";
		 
		 tab_5.className = "";

         content_5.style.display = "none";
         }

         else if(elem == tab_3)
		 {

         tab_3.className = "selected";

         content_3.style.display = "block";



         tab_1.className = "";

         content_1.style.display = "none";
         
		 tab_2.className = "";

         content_2.style.display = "none";
        
         tab_4.className = "";

         content_4.style.display = "none";
         
		 tab_5.className = "";

         content_5.style.display = "none";
   
        }
        else if(elem == tab_4)
		{

         tab_4.className = "selected";

         content_4.style.display = "block";



         tab_1.className = "";

         content_1.style.display = "none";
         
		 tab_2.className = "";

         content_2.style.display = "none";
        
         tab_3.className = "";

         content_3.style.display = "none";
		 
		 tab_5.className = "";

         content_5.style.display = "none";
		 
		  }
        else if(elem == tab_5)
		{

         tab_5.className = "selected";

         content_5.style.display = "block";



         tab_1.className = "";

         content_1.style.display = "none";
         
		 tab_2.className = "";

         content_2.style.display = "none";
        
         tab_3.className = "";

         content_3.style.display = "none";
		 
		 tab_4.className = "";

         content_4.style.display = "none";
		 }
    }
}