[danik.js]

<select id="abc">
    <option value="1">1</option>
    <option value="2">3</option>
    <option value="3">4</option>
    <option value="4">5</option>
    <option value="5">5</option>
</select>
<select id="cde">
    <option value="1">1</option>
    <option value="2">3</option>
    <option value="3">4</option>
    <option value="4">5</option>
    <option value="5">5</option>
</select>
<script>
(function(){
    var selects = document.querySelectorAll('select');
    for (var i = 0, select; select = selects[i]; i++) {
        if (localStorage[select.id] !== undefined) {
            select.selectedIndex = localStorage[select.id];
        }
        select.onchange = function() {
            localStorage[this.id] = this.selectedIndex;
        }
    }
})()
</script>