The error you mention is triggered in CGI::Ajax::insert_js_in_head, and it means that the necessary javascript can't be inserted into your html document.

I think the error is caused by your passing a reference to the template output. The way I understand the CGI::Ajax docs, you should either pass a coderef, or a string, to build_html. The quick fix to your code is therefore:

sub main {
    
    my $self = shift;
    my $q = $self->query;  # the CGI object
    my $tmpl = $self->load_tmpl( 'main.tmpl' );

    $pjx->build_html( $q, $tmpl->output );          # <-- no reference
    
}
[download]