var rn = 1;
var rand = Math.random();
rn = Math.floor(rand*10+1);
switch (rn)
{
case 0:
case 1:
case 2:
case 3:
case 4:
case 5:
case 6:
case 7:
case 8:
case 9:
case 10:
//general
document.write('
');
break;
default:
//google
document.write('');
break
}