A How To

<?php
function reqFields(&$fields, &$vMsg, &$rMsg) {
	global $modx;
		
		if($fields['goat'] == 'no'){
			if(!$fields['why']){
				$rMsg['why'] = "No Why";	
			}
		}elseif($fields['goat'] == 'yes'){
			//nothing to do or whatever you wanna do
		}else{
		        $rMsg['goat'] = "Goat Error";
			return false;
		}

	return true;
}
?>

<?php
function reqFields(&$fields, &$vMsg, &$rMsg, &$rClass) { //<-- $rClass holds assoc. array of class names for fields (for eForm > 1.4.4)
	global $modx;

		/* optional. load parameter values for error css classes */
		$req_class_name = $modx->event->params['requiredClass'];
		$inv_class_name = $modx->event->params['invalidClass'];
		/* end optional */
		if($fields['goat'] == 'no'){
			if(!$fields['why']){
				$rMsg['why'] = "Why";  //<-- should be the field name or desciption only
				$rClass['why'] .= $rClass['why'] ? ' ' . $req_class_name : $req_class_name; //optional.
			}
		}elseif($fields['goat'] == 'yes'){
			//nothing to do or whatever you wanna do
		}else{
		        $vMsg['goat'] = "Goat Error";  //<-- use $vMsg not $rMsg. Add a full error message
		        $rClass['goat'] .= $rClass['goat'] ? ' ' . $inv_class_name : $inv_class_name; //optional.
			///return false; <-- do not return false as this will produce a blank screen
		}

	return true;
}
?>

<?php
function evalSnippet($snippet, $params) {
        $etomite= $modx= & $this;

        $modx->event->params= & $params; // store params inside event object
        if (is_array($params)) {
            extract($params, EXTR_SKIP);
        }
.......

[!showEventParams!]
[!eForm? &formid=`test_1` &tpl=`test1` &thankyou=`test1Report` &noemail=`1`  &eFormOnValidate=`showEventParams`!]

<?php
if( !function_exists('showEventParams') ) {
    function showEventParams(&$fields){
        global $modx;
        $fields['event_params'] ='<pre>'.print_r($modx->event->params,true).'</pre>';
        return true;
    }
}

return '';
?>

[+validationmessage+]
--------form---------------
<form method="post" action="[~[*id*]~]" id="test_1">
    <p><label for="name">Name </label> <input type="text" name="fullname" size="30" maxlength="60" eform="Name::1" /></p>
    <p><input class="verify" type="submit" name="Submit" value="Send"></p>
</form>
--------report-------------
<p>Here's the form results:</P
<p>Name: [+fullname+]</p>
<p>[+event_params+]</p>

Here's the form results:

Name: TobyL

Array
(
    [snipPath] => D:/www/eFormDev/assets/snippets/eform/
    [snipFolder] => eform
    [vericode] => 
    [formid] => test_1
    [from] => [email protected]
    [fromname] => Modx CMF demo
    [to] => [email protected]
    [cc] => 
    [bcc] => 
    [subject] => 
    [ccsender] => 0
    [sendirect] => 0
    [mselector] => 0
    [mobile] => 
    [mobiletext] => 
    [autosender] => 
    [autotext] => 
    [category] => 0
    [keywords] => 
    [gid] => 64
    [noemail] => 1
    [saveform] => 1
    [tpl] => test1
    [report] => 
    [allowhtml] => 0
    [replyto] => 
    [language] => english
    [thankyou] => test1Report
    [isDebug] => 3
    [reportAbuse] => 
    [disclaimer] => 
    [sendAsHtml] => 
    [sendAsText] => 
    [sessionVars] => 
    [postOverides] => 0
    [eFormOnBeforeMailSent] => 
    [eFormOnMailSent] => 
    [eFormOnValidate] => showEventParams
    [eFormOnBeforeFormMerge] => 
    [eFormOnBeforeFormParse] => 
    [cssStyle] => 
    [jScript] => 
    [submitLimit] => 0
    [protectSubmit] => 1
    [requiredClass] => required
    [invalidClass] => invalid
    [runSnippet] => 
    [autoSenderName] => 
    [version] => 1.4.4
)