if condition in qweb report odoo 9
in the invoice report I want implement the following logic:
<span t-if="o.x_onlineId != ''">
<div class="col-xs-2" style="width:180px">
The problem is that the if condition do not work. The field "Web Id" is always printed in the invoice even the fiel x_onlineId is empty.
I have already tested the following syntax
<span t-if=" not o.x_onlineId == ''">
It also did not work.
The question is how it is possible to check for an empty value in a field?
Has someone an idea.
Thanks in advanced