function   showdiv1()   {   
          Div1   =   document.getElementById("div1");   
		  Div2   =   document.getElementById("div2");
		  Div3   =   document.getElementById("div3"); 
		  Div4   =   document.getElementById("div4");
          Div1.style.display   =   "block";   
          Div2.style.display   =   "none"; 
		  Div3.style.display   =   "none"; 
		  Div4.style.display   =   "none"; 
}   
    
function   showdiv2()   {   
		  Div1   =   document.getElementById("div1");   
		  Div2   =   document.getElementById("div2");
		  Div3   =   document.getElementById("div3");  
		  Div4   =   document.getElementById("div4");
			  Div1.style.display   =   "none";   
              Div2.style.display   =   "block"; 
			  Div3.style.display   =   "none"; 
			  Div4.style.display   =   "none"; 
} 

function   showdiv3()   {   
		  Div1   =   document.getElementById("div1");   
		  Div2   =   document.getElementById("div2");
		  Div3   =   document.getElementById("div3");   
		  Div4   =   document.getElementById("div4");
			  Div1.style.display   =   "none";   
              Div2.style.display   =   "none"; 
			  Div3.style.display   =   "block"; 
			  Div4.style.display   =   "none"; 
} 

function   showdiv4()   {   
		  Div1   =   document.getElementById("div1");   
		  Div2   =   document.getElementById("div2");
		  Div3   =   document.getElementById("div3"); 
		  Div4   =   document.getElementById("div4");
			  Div1.style.display   =   "none";   
              Div2.style.display   =   "none"; 
			  Div3.style.display   =   "none";   
              Div4.style.display   =   "block"; 
}