How to check if some variable is present in twig template in symfony2

Question

IN the every template i need to use this ststement

{{ form_stylesheet(form) }}
{{ form_javascript(form) }}

The the template gives error if the page is not haviing any form variable ie its normal page.

Is there any way that i can check if form is present then load those otherwise not

if (form.present) then
{{ form_stylesheet(form) }}
    {{ form_javascript(form) }}

Answer 1

{% if form is defined  %}
    {{ form_stylesheet(form) }}
    {{ form_javascript(form) }}
{% endif %}