Mura CMS : This is an example of how to perform server side validation of Mura CMS form submissions and display an error message to the end user. This leverages the onBeforeFormSubmitSave and the onFormSubmitErrorRender (as of 6.1) methods.

mura-onBeforeFormSubmitSave-onFormSubmitErrorRender.cfm

<cfscript>
	// Drop this in your Site or Theme eventHandler.cfc
	public any function onBeforeFormSubmitSave($) {
		// reference to the formBean
		var formBean = arguments.$.event('formDataBean');

		// example on how to create some errors
		var error = '';
		var errors = {};

		// Check for any required fields/attributes, and create an error if missing
		if ( !Len($.event('message')) ) {
			StructAppend(errors, {'error1': 'Message is required.'});
		}
		// if ( !Len(newBean.getValue('someExtendedAttribute'))) {
		// 	StructAppend(errors, {'error2': 'Some Extended Attribute is required.'});
		// }

		// if there's errors
		if ( !StructIsEmpty(errors) ) {
			for ( error in errors ) {
				formBean.getErrors()[error] = errors[error];
			}
			arguments.$.event('acceptdata', false);
		} else {
			// no errors, so we're good!
			// do whatever else you want to do here (e.g. log something, etc.)
		}
	}

	public any function onFormSubmitErrorRender($) {
		var str = '';
		var formBean = arguments.$.event('formDataBean');
		var error = '';
		var errors = {};
		savecontent variable='str' {
			if ( !StructIsEmpty(formBean.getErrors()) ) {
				WriteOutput('<div class="alert alert-danger"><p><strong>Please review the following error(s)</strong></p><ul>');
				errors = formBean.getErrors();
				for ( error in errors ) {
					WriteOutput('<li>' & errors[error] & '</li>');
				}
				WriteOutput('</ul></div><p><a href="javascript:history.go(-1);">Try again &raquo;</a></p>');
			}
		}
		return str;
	}
</cfscript>

+1 on Vipin's comment. Once I changed to grab the formDataBean, it worked as expected.

@vipinunnithan & @Luke-Wilson, I've updated the Gist to use formDataBean vs. formBean. Thanks!