calculation in adobe livecycle

i had made a form using adobe livecylce designer ES2 and i want to get the standard deviation for a multiple numeric cells values.. in adobe acrobate i was using this javascript

var MyValues = new Array();

var MyFields = new Array("F0VerHR", "F1VerHR", "F1secondVerHR", "F2VerHR", "F3VerHR");

var oField;

var nField;

for(var i = 0; i < MyFields.length; i++)

{

  nField = '';

  nField = GetField(this, MyFields[i]).valueAsString;

  if(nField != "") MyValues.push(Number(nField));

}

event.value = standardDeviation(MyValues);

but this code dose not work with livecycle designer.. can you help me please in the correct code

thanks alot