使用2种不同的背景样式运行foreach

<?php
$data = array("apple", "banana", "orange", "grape");

foreach ($data as $key => $value) {
    if ($key % 2 == 0) {
        $class = "even"; // 偶数索引元素的背景样式类名
    } else {
        $class = "odd"; // 奇数索引元素的背景样式类名
    }

    echo '<div class="' . $class . '">' . $value . '</div>';
}
?>

var data = ["apple", "banana", "orange", "grape"];

data.forEach(function(value, index) {
    var style = (index % 2 == 0) ? "background-color: #f2f2f2;" : "background-color: #ffffff;";
    var element = document.createElement("div");
    element.setAttribute("style", style);
    element.textContent = value;
    document.body.appendChild(element);
});