it work with Executions.getCurrent().getParameter("codigoUnicoCliente")
but I do not know what myFunction() do, so I replace it with this code:
<form id="frm1" action="test.zul" METHOD="POST">
<input type="hidden" id="codigoUnicoCliente" name="codigoUnicoCliente" value="00000050055255">
<input type="submit" value="Invar Spu POST URL">
</form>
Then, I use following in test.zul
<window apply="org.zkoss.bind.BindComposer" viewModel="@id('vm') @init('test.vm.TestViewModel')">
and then in TestViewModel
@Init
public void init(@ContextParam(ContextType.SESSION) Session session) {
System.out.println(Executions.getCurrent().getParameter("codigoUnicoCliente"));
}
and work like charm :)