function validate_required(field,alerttxt)
{
with (field)
{
if (value==null||value=="")
  {alert(alerttxt);return false;}
else {return true}
}

}function validate_form(thisform)
{
with (thisform)
{
if (validate_required(txtsearch,"Please insert text to search !")==false)
  {txtsearch.focus();return false;}
}
}