Mikhail Kupriyanov

<?foreach ($arResult["PROPERTIES"] as $i => $arProp):?>
                                                <?if(!empty($arProp["VALUE"])):?>
                                                        <table id="table1">
                                                               <tr style="background-color:"<?= $i%2 ? 'green' : 'white' ?>">
// ...

#table1 tr:nth-child(even) { background: #0f0; }
#table1 tr:nth-child(odd) { background: #fff; }