function userEventBeforeLoad(type, form, request){
    var domain = '57e36ca7.ngrok.io'; //an array of domains that is possible to use these credentials
    var username = 'billy';
    var password = 'password123';
    var script = 'customscript75'; //the script that will eventually use the nlapiRequestURLWithCredentials call
    var cred_group = form.addFieldGroup("_credgroup", "Credential Fields Generated in Code");
    var cred1 = form.addCredentialField('custpage_username', username, domain, script, null, false, "_credgroup");
    var cred2 = form.addCredentialField('custpage_password', password, domain, script, null, false, "_credgroup");
}

function userEventBeforeSubmit(){
    nlapiSetFieldValue('custentity_username', nlapiGetFieldValue('custpage_username'));
    nlapiSetFieldValue('custentity_password', nlapiGetFieldValue('custpage_password'));
    nlapiSetFieldValue('custentity_password', nlapiGetFieldValue('custpage_password'));
    nlapiSetFieldValue('custentitycustrecord_testing', 'worked');
    return true;
}