function clearField(field) {
  if (field.value == field.defaultValue) 
    field.value = "";
}

function checkField(field) {
  if (field.value == "") 
    field.value = field.defaultValue;
}

function zaznacz(formname,checkname)
{
var el_collection=eval("document.forms."+formname+"."+checkname)
if (el_collection.checked==false)
 el_collection.checked=true
else
 el_collection.checked=false
}