// function to validate input

function checkInput() {

  var missing=focusVal=""
  df=document.forms[0]
  arg_num = arguments.length
  j=1

  for(i=0;i<arg_num;i=i+2) {
     current_val = eval("df."+arguments[i]+".value")
     if ( current_val == "" ) {
            missing += "- " + arguments[j] + "\n"
        if ( focusVal=="" ) focusVal = arguments[i]
         }
         j=j+2
  }

  if (missing != "") {
    alert("The following information is required:\n"+missing)
    eval("df."+focusVal+".focus()")
    return false
  } else {
    return true
  }
}