function a1()
	{
    document.getElementById("bb1").className ="hov";
    document.getElementById("bb2").className ="sep";
    document.getElementById("bb3").className ="sep";
    document.getElementById("bb4").className ="";
		
	document.getElementById("b1").style.display ="block";
    document.getElementById("b2").style.display ="none";
	document.getElementById("b3").style.display ="none";
	document.getElementById("b4").style.display ="none";
	}
	function a2()
	{

    document.getElementById("bb2").className ="hov";
    document.getElementById("bb1").className ="sep";
    document.getElementById("bb3").className ="sep";
    document.getElementById("bb4").className ="";

	document.getElementById("b2").style.display ="block";
    document.getElementById("b1").style.display ="none";
	document.getElementById("b3").style.display ="none";
	document.getElementById("b4").style.display ="none";
	}
	function a3()
	{
    document.getElementById("bb3").className ="hov";
    document.getElementById("bb2").className ="sep";
    document.getElementById("bb1").className ="sep";
    document.getElementById("bb4").className ="";

	document.getElementById("b3").style.display ="block";
    document.getElementById("b1").style.display ="none";
	document.getElementById("b2").style.display ="none";
    document.getElementById("b4").style.display ="none";
	}
	function a4()
	{
    document.getElementById("bb4").className ="hov";
    document.getElementById("bb2").className ="sep";
    document.getElementById("bb3").className ="sep";
    document.getElementById("bb1").className ="sep";
	
	document.getElementById("b4").style.display ="block";
    document.getElementById("b1").style.display ="none";
	document.getElementById("b2").style.display ="none";
	document.getElementById("b3").style.display ="none";
	}