function OpenDiv(id) { 
 for (i=1;i<=4;i++) { // so you can add more than 2 
 var divname = 'div'+i; 
 var divStyle = document.getElementById(divname).style; 
 divStyle.display=(id==divname)?'block':'none'; 
 } 
} 

function OpenDiv1(id) { 
 for (i=1;i<=3;i++) { // so you can add more than 2 
 var divname = 'div'+i; 
 var divStyle = document.getElementById(divname).style; 
 divStyle.display=(id==divname)?'block':'none'; 
 } 
} 

function OpenDiv2(id) { 
 for (i=1;i<=3;i++) { // so you can add more than 2 
 var divname = 'div'+i; 
 var divStyle = document.getElementById(divname).style; 
 divStyle.display=(id==divname)?'block':'none'; 
 } 
}