Javascript question - Copy drop down select lists from one form field to another

I am new to Javascript and having trouble figuring out how to copy drop down select lists from one form field to another.

Here is what I have so far:

function FillShipping(f){ if(f.shippingtoo.checked == true)

{

{

f.email1.value = f.email.value;

f.fullName1.value = f.fullName.value;

f.address1.value = f.address.value;

f.address3.value = f.address2.value;

f.city1.value = f.city.value;

f.postCode1.value = f.postCode.value;

f.phone11.value = f.phone1.value;

f.phone22.value = f.phone2.value;

f.phone33.value = f.phone3.value;

f.cell11.value = f.cell1.value;

f.cell22.value = f.cell2.value;

f.cell33.value = f.cell3.value;

}

}

else {

f.email1.value = '';

f.fullname1.value = '';

f.address1.value = '';

f.address3.value = '';

f.city1.value = '';

f.postCode1.value = '';

f.phone11.value = '';

f.phone22.value = '';

f.phone33.value = '';

f.cell11.value = '';

f.cell22.value = '';

f.cell33.value = '';

}

} (link to html http://www.echanigraphics.com/test/checkout.html)

Could someone help please?

Thanks,

Elda