JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
<li id="truc1">zaze</li>
<li id="truc_1">rezret</li>
<li id="truc2">tryt</li>
<li id="truc_2">ertzertyret</li>
<li id="truc3">reterztrze</li>
<li id="truc_3">retzerzt</li>
<li id="truc4">erztzert</li>
<li id="truc_4">ertrtezt</li>
</ul>

JavaScript

$(function(){

$liavec_ = $("li").filter( function(){ return $(this).attr('id').match(/_/);});
$liavec_.each( function() { $(this).css('color', "red");} );
})