function findform() { 
  var i;
  d=document; 
  for (i=0;i<d.forms.length;i++) x=d.forms[i];
  return x;
}

function doPostBack(ctn) {
		df = findform()
        df.pbctn.value = ctn.name;
        df.pbval.value = ctn.value;
        df.submit();
}