function updateHTML(id, val)
{ var elem = document.getElementById(id);
  elem.innerHTML = val;
}

function firstword(v)
{ return v.split(" ")[0];
}

function choose_format(cellid)
{ elem=document.getElementById(cellid);
  d=elem.innerHTML;

  previd=document.getElementById('selcell').value;
  prevcell=document.getElementById(previd);

  if (!(prevcell==null))
    prevcell.style.background='white';

  document.getElementById(cellid).style.background='orange';
  document.getElementById('selcell').value=cellid;

  // get row and column from cellid

  p=cellid.indexOf('R');

  col=cellid.substr(0,p);
  row=cellid.substr(p);

  sc='C0'+row;
  fmt=firstword(document.getElementById(sc).innerHTML);

  if (row<'R4')
    sc=col+'R0';
  else
    sc=col+'R4';

  psize=firstword(document.getElementById(sc).innerHTML);

  // try to match this specification
  var t=fmt+' '+psize+' cm';

  optlist=document.getElementById('item-options');

  i=0;
  while ( (i<optlist.length) && !(t == optlist.options[i].value) )
    i++;

  if (i<optlist.length)
    optlist.selectedIndex=i;
  else
    optlist.selectedIndex=-1;
}

function highlight()
{ optlist=document.getElementById('item-options');

  var sf=optlist.value;
  if (sf=="")
    return;

  parts=sf.split(" ");
  fmt=parts[0];
  sz=parts[1];

  parts=sz.split("x");
  is_square=(parts[0]==parts[1]);

  r=(is_square) ? 4:0;
  cmax=(is_square) ? 6:5;
  rmax=r+3;

  c=0;
  gotcolumn=false;

  while ((c<cmax) && (!gotcolumn))
  { c++;
    cellid='C'+c+'R'+r;
    cell=document.getElementById(cellid);
    gotcolumn=(firstword(cell.innerHTML) == sz);
  }

  if (!gotcolumn)
    return;        // give up now

  match=false;

  while (  (r < rmax) && !(match)  )
  { r++;
    cellid='C0R'+r;
    cell=document.getElementById(cellid);
    match=(firstword(cell.innerHTML) == fmt);
  }

  if (match)
  { cellid='C'+c+'R'+r;

    previd=document.getElementById('selcell').value;
    prevcell=document.getElementById(previd);

    if (!(prevcell==null))
      prevcell.style.background='white';

    document.getElementById(cellid).style.background='orange';
    document.getElementById('selcell').value=cellid;
  }
}

function reveal(id,show)
{ if (show)
    document.getElementById(id).style.visibility='visible';
  else
    document.getElementById(id).style.visibility='hidden';
}

function tickall()
{ if (document.getElementById('everything').checked)
  { document.getElementById('photographs').checked=true;
    document.getElementById('paintings').checked=true;
    document.getElementById('cards').checked=true;
    document.getElementById('exhibitions').checked=true;
  }
}

function check_email(str)
{ if (str.indexOf("'")>=0)
    return false;

  if (str.indexOf(",")>=0)
    return false;

  ereg=new RegExp("^.+@.+\\..+$");
  return ereg.test(str);
}

function postit(form,flag)
{ switch (flag)
  { case 2:
      if (form.fromemail.value.length==0)
      { alert("Please enter your email address");
        form.fromemail.focus();
        return false;
      }

      if (!check_email(form.fromemail.value))
      { alert("Please check your email address");
        form.fromemail.focus();
        return false;
      }

      if (form.fullname.value.length==0)
      { alert("Please tell us your name");
        form.fullname.focus();
        return false;
      }

      form.action="utils/galmailer.php";
      reveal('sendbutton',false);
      reveal('ack',true);
      break;

    default: return;
  }

  form.method="post"
  form.submit();
}