jquery - How can a class be added to a div via php? -

i have h tag below,

<h3 id="reply-title"> 

& needed add class remotely.

(this h3 tag located in comment-template.php. (line 1554) of wordpress core file in case wondering why can't hard code class it.)

i've done 1 line jquery (add class on .load) now, concerned since if javascript turned off, class won't added.

i have little knowledge of php , wondering if can done in php. i've done research on google & couldn't find reference.

any php expert can provide insight?

this in general bad practice, can this:

echo "<script>$('#reply-title').addclass('class')</script>"; 

but repeat: this bad practice. javascript must in .js files, , php in .php files.

however, if javascript disabled, think can't want.

hope helps.