function checkthis(a)
{
if (!a.checked)
{
div1.style.display = "none";
}
else
{
div1.style.display ='';
}
}
{
if (!a.checked)
{
div1.style.display = "none";
}
else
{
div1.style.display ='';
}
}
if (!a.checked){div1.style.display = "none";}
else {div1.style.display = "block";}
}
{
if (!a.checked)
{
div1.style.display="none"
}
else
{
div1.style=""}
}