Help with js implementation

Dear Sirs,

Thank you by this plugin!

Please, is it possible to insert a tag at HTML? I want to insert my facebook pixel just at posts of a specific category. I have created an if condition at js, but didn′t have sucess… could you take a look?

<script>

if(document.querySelector(‘.post-cats’).innerHTML.includes(‘Xxxxxxx‘)){

var pixelDec = document.createElement(‘div’);
pixelDec.innerHTML = [‘<script>
!function(f,b,e,v,n,t,s)
{if(f.fbq)return;n=f.fbq=function(){n.callMethod?
n.callMethod.apply(n,arguments):n.queue.push(arguments)};
if(!f._fbq)f._fbq=n;n.push=n;n.loaded=!0;n.version=’2.0′;
n.queue=[];t=b.createElement(e);t.async=!0;
t.src=v;s=b.getElementsByTagName(e)[0];
s.parentNode.insertBefore(t,s)}(window, document,’script’,
‘https://connect.facebook.net/en_US/fbevents.js&#8217;);
fbq(‘init’, ‘00000000000000000’);
fbq(‘track’, ‘PageView’);
</script>
<noscript>
<img height=‘1’ width=‘1’ style=‘display:none’
src=‘https://www.facebook.com/tr?id=00000000000000000&ev=PageView&noscript=1’/>
</noscript>
‘];
document.body.appendChild(pixelDec);

}

</script>

Could have a solution here at this plugin?

Thanks and Regards,
Tony