On my page I would like part of a string to be bold, however the string value is created from a Jekyll variable. Effectively, I want to pre-process the string with some function where the jekyll variable is the input.

In my main html file I have:

{% for post in site.posts %}
  {% include archive.html %}
{% endfor %}

Inside archive.html I have:

<p> {{ post.var }} </p>

I'm assuming javascript is the way to go about this using a function along the lines of:

function makeSubStrBold(str) {
  var substr = "something"
  var strRegExp = new RegExp(substr, 'g');
  return str.replace(strRegExp, '<b>'+substr+'</b>');
}

So if post.var = "this is something", what gets actually displayed in html is "this is <b> something </b>"

How could I use this javascript function to pre-process the string from the jekyll variable? Is this maybe possible in css?