Escaping ampersand in custom attribute using Thymeleaf 3? - thymeleaf

Question

Is it possible to do basic escaping (of ampersand, in my case) when generating a custom attribute? I have tried many ways (with normal escaping, th:text, th:utext, th:attr for all the dynamic attributes, substituting a custom tag in my Spring code), unfortunately found just some workaround, which is listed below.
Basically, it's about an AngularJS application with a piece of Thymealeaf 3 template:
<script th:inline="javascript">
function customSubmit() {
/*<![CDATA[*/
return /*[(${DIALOG_NAME} + '.$valid && submit()')]*/ null;
/*]]>*/
}
</script>
<form th:name="${DIALOG_NAME}"
th:action= "'/' + ${MODULE} + '.' + ${DIALOG_NAME}"
th:ng-app="${DIALOG_NAME} + 'App'"
th:ng-controller="${DIALOG_NAME} + 'Controller'"
ng-submit="customSubmit()"
...
>
...
</form>
What I am trying to make is one construct like
th:ng-submit="some Thymeleaf expression"
that generates the custom attribute value with the && within:
ng-submit="someDialog.$valid && submit()"
without any function redirection like in the workaround above.
Beside extending Thymeleaf (I am using SpringStandard dialect), is any straightforward way to generate such strings?
Thank you for any suggestion.

Answer 1

Ampersands (&) should be HTML-escaped in tag attributes so you can do it like this:
th:attr="ng-submit='some thymeleaf with && in it'"
EDIT:
If you also want to reference a value of some model attribute in the final form attribute value you have to use the expression preprocessing like this:
<form th:attr="ng-submit='__${DIALOG_NAME}__' + ' some ampersand && in it'">
</form>