ufaclub,
тоже самое с атрибутом data-...
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<script>
document.addEventListener("DOMContentLoaded", function() {
let cover1 = document.querySelector("#mark1");
let cover2 = document.querySelector("#mark2");
let options = [...cover1.options];
let opts = [...cover2.options];
cover1.addEventListener("change", function() {
let cls = options[this.selectedIndex].dataset.class;
let up = opts.filter(({
dataset
}) => dataset.class === cls || !cls);
cover2.options.length = 0;
cover2.append(...up)
})
})
</script>
</head>
<body>
<select id="mark1" name="cover1" size="5">
<option>select</option>
<option data-class="cs1" value="1">cs1</option>
<option data-class="cs1" value="2">cs1</option>
<option data-class="cs0" value="3">cs0</option>
<option data-class="cs2" value="4">cs2</option>
</select>
<select id="mark2" name="cover2" size="5">
<option data-class="cs1" value="1">cs1</option>
<option data-class="cs1" value="2">cs1</option>
<option data-class="cs2" value="3">cs2</option>
<option data-class="cs2" value="4">cs2</option>
</select>
</body>
</html>