function change1(n){
var f='link';

for(var i=1;i<=8;i++)
{

document.getElementById(f+i).style.background = 'none';

}
for(var i=9;i<=18;i++)
{
document.getElementById(f+i).style.background = 'white';
}


if(n=='link9'||n=='link10'||n=='link11'||n=='link12'||n=='link13'||n=='link14'||n=='link15')
{

document.getElementById('link2').style.background = 'orange';
}
if(n=='link16'||n=='link17' || n=='link18')
{
document.getElementById('link4').style.background = 'orange';
}



if(n==n)
{

document.getElementById(n).style.background = 'orange';
}

}