JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
   <li id='e1'>e1</li>
   <li id='e2'>e2</li>
   <li id='e3'>e3</li>
   <li id='e4' style="z-index:4">e4</li>
   <li id='e5'>e5</li>
<ul>

CSS

#e1 {
    z-index:1;
    color:#000000;
}
#e2 {
    z-index:2;
    color:#000000;
}
#e3 {
    z-index:3;
    color:#000000;
}
#e4 {
    z-index:4;
    color:#FFFFFF;
}
#e5 {
    z-index:5;
    color:#000000;
}

JavaScript

var elem;
var elems = $("li");

 for(var i=0; i<elems.length; i++) {
    console.log($(elems[i]).css('color'));
    if($(elems[i]).css('color') == '#FFFFFF') {
        elem = elems[i];  //assign elem we found
        break;            //exit loop early
    }
 }

console.log($(elem).html());