function show_tab1()
    {
	nav1.className="tab_on";
	nav2.className="tab_off";
	nav3.className="tab_off";
	nav4.className="tab_off";
	nav5.className="tab_off";
	nav6.className="tab_off";
	nav7.className="tab_off";
	nav8.className="tab_off";	
    }
function show_tab2()
    {
	nav1.className="tab_off";
	nav2.className="tab_on";
	nav3.className="tab_off";
	nav4.className="tab_off";
	nav5.className="tab_off";
	nav6.className="tab_off";
	nav7.className="tab_off";
	nav8.className="tab_off";	
    }
function show_tab3()
    {
	nav1.className="tab_off";
	nav2.className="tab_off";
	nav3.className="tab_on";
	nav4.className="tab_off";
	nav5.className="tab_off";
	nav6.className="tab_off";
	nav7.className="tab_off";
	nav8.className="tab_off";	
    }
function show_tab4()
    {
	nav1.className="tab_off";
	nav2.className="tab_off";
	nav3.className="tab_off";
	nav4.className="tab_on";
	nav5.className="tab_off";
	nav6.className="tab_off";
	nav7.className="tab_off";
	nav8.className="tab_off";	
    }
function show_tab5()
    {
	nav1.className="tab_off";
	nav2.className="tab_off";
	nav3.className="tab_off";
	nav4.className="tab_off";
	nav5.className="tab_on";
	nav6.className="tab_off";
	nav7.className="tab_off";
	nav8.className="tab_off";	
    }
function show_tab6()
    {
	nav1.className="tab_off";
	nav2.className="tab_off";
	nav3.className="tab_off";
	nav4.className="tab_off";
	nav5.className="tab_off";
	nav6.className="tab_on";
	nav7.className="tab_off";
	nav8.className="tab_off";	
    }
function show_tab7()
    {
	nav1.className="tab_off";
	nav2.className="tab_off";
	nav3.className="tab_off";
	nav4.className="tab_off";
	nav5.className="tab_off";
	nav6.className="tab_off";
	nav7.className="tab_on";
	nav8.className="tab_off";	
    }

function show_con1(){
	content1.style.display="block";
	}
function show_con2(){
	content2.style.display="block";
	}
function show_con3(){
	content3.style.display="block";
	}
function show_con4(){
	content4.style.display="block";
	}
function show_con5(){
	content5.style.display="block";
	}
function show_con6(){
	content6.style.display="block";
	}
function show_con7(){
	content7.style.display="block";
	}
function hide_con1(){
	content1.style.display="none";
	}
function hide_con2(){
	content2.style.display="none";
	}
function hide_con3(){
	content3.style.display="none";
	}
function hide_con4(){
	content4.style.display="none";
	}
function hide_con5(){
	content5.style.display="none";
	}
function hide_con6(){
	content6.style.display="none";
	}
function hide_con7(){
	content7.style.display="none";
	}
function chgMenuO(n)
{ for(i=1;i<5;i++)
     if(i!=n)
	    { document.getElementById("btn"+i).className="btn_menub_chg";
		  document.getElementById("div"+i).style.display="none";
		}
     else
	    { document.getElementById("btn"+n).className="btn_menuy_chg";
		  document.getElementById("div"+n).style.display="inline";
		}
}
function chgtab8(){
	document.getElementById("btn"+8).className="btn_menuy_chg";
	document.getElementById("div"+8).style.display="block";
	document.getElementById("btn"+9).className="btn_menub_chg";
	document.getElementById("div"+9).style.display="none";
	}
function chgtab9(){
	document.getElementById("btn"+9).className="btn_menuy_chg";
	document.getElementById("div"+9).style.display="block";
	document.getElementById("btn"+8).className="btn_menub_chg";
	document.getElementById("div"+8).style.display="none";
	}