var nbsp = 160;    // non-breaking space char

var node_text = 3; // DOM text node-type

var emptyString = /^\s*$/

var glb_vfld;      // retain vfld for timer thread



// -----------------------------------------

// trim

// Trim leading/trailing whitespace off string

// -----------------------------------------



function trim(str)

{

  return str.replace(/^\s+|\s+$/g, '')

};



// -----------------------------------------

// msg

// Display warn/error message in HTML element

// commonCheck routine must have previously been called

// -----------------------------------------



function msg(fld,     // id of element to display message in

             msgtype, // class to give element ("warn" or "error")

             message) // string to display

{

  // setting an empty string can give problems if later set to a 

  // non-empty string, so ensure a space present. (For Mozilla and Opera one could 

  // simply use a space, but IE demands something more, like a non-breaking space.)

  var dispmessage;

  if (emptyString.test(message)) 

    dispmessage = String.fromCharCode(nbsp);    

  else  

    dispmessage = message;



  var elem = document.getElementById(fld);

  elem.firstChild.nodeValue = dispmessage;  

  

  elem.className = msgtype;   // set the CSS class to adjust appearance of message

};



// -----------------------------------------

// commonCheck

// Common code for all validation routines to:

// (a) check for older / less-equipped browsers

// (b) check if empty fields are required

// Returns true (validation passed), 

//         false (validation failed) or 

//         proceed (don't know yet)

// -----------------------------------------



var proceed = 2;  



function commonCheck    (vfld,   // element to be validated

                         ifld,   // id of element to receive info/error msg

                         reqd)   // true if required

{

  if (!document.getElementById) 

    return true;  // not available on this browser - leave validation to the server

  var elem = document.getElementById(ifld);

  if (!elem.firstChild)

    return true;  // not available on this browser 

  if (elem.firstChild.nodeType != node_text)

    return true;  // ifld is wrong type of node  

  if (emptyString.test(vfld.value)) {

    if (reqd) {

      msg (ifld, "error", "ERROR: required");  

      return false;

    }

    else {

      msg (ifld, "warn", "");   // OK

      return true;  

    }

  }

  return proceed;

}



// -----------------------------------------

// validateGas

// Validate amount

// Returns true if OK 

// -----------------------------------------



function validateGas    (vfld,   // element to be validated

                         ifld,   // id of element to receive info/error msg

                         reqd)   // true if required

{

  var stat = commonCheck (vfld, ifld, reqd);

  if (stat != proceed) return stat;



  var tfld = trim(vfld.value);

  var gasRE = /^[0-9]{1,6}$/

  if (!gasRE.test(tfld)) {

    msg (ifld, "error", "ERROR: Remove invalid character");

    return false;

  }



  if (tfld>=200000) {

    msg (ifld, "error", "amount to high");

    return false;

  }



  if (tfld>5000) msg (ifld, "warn", "Check amount entered is correct");

  else {

    if (tfld<2) msg (ifld, "warn", "Amount to low");

    else        msg (ifld, "warn", "");

  }

  return true;

};



// -----------------------------------------

// validateElec

// Validate amount

// Returns true if OK 

// -----------------------------------------



function validateElec    (vfld,   // element to be validated

                         ifld,   // id of element to receive info/error msg

                         reqd)   // true if required

{

  var stat = commonCheck (vfld, ifld, reqd);

  if (stat != proceed) return stat;



  var tfld = trim(vfld.value);

  var elecRE = /^[0-9]{1,6}$/

  if (!elecRE.test(tfld)) {

    msg (ifld, "error", "ERROR: Remove invalid character");

    return false;

  }



  if (tfld>=200000) {

    msg (ifld, "error", "Amount to high");

    return false;

  }



  if (tfld>5000) msg (ifld, "warn", "Check amount entered is correct");

  else {

    if (tfld<2) msg (ifld, "warn", "Amount to low");

    else        msg (ifld, "warn", "");

  }

  return true;

};