为什么不设置此cookie？

Question

此代码的目标是为页面的背景色设置cookie。我不明白为什么无法设置Cookie。

<select id="ddlTheme" onchange="setColorCookie()">
    <option value="Select Color">Select Color</option>
    <option value="red">Red</option>
    <option value="green">Green</option>
    <option value="blue">Blue</option>
</select>

<script>
window.onload = function() {
    if(document.cookie.length != 0) {
        var nameValueArray = document.cookie.split("=");
        document.getElementById("ddlTheme").value = nameValueArray[1];
        document.body.style.backgroundColor = nameValueArray[1];
        console.log("Window onload happened sir!");
    }
}
function setColorCookie() {
    var selectedValue = document.getElementById("ddlTheme").value;
    if (selectedValue != "Select Color") {
        document.body.style.backgroundColor = selectedValue;
        var d = new Date();
        d.setTime(d.getTime() + (exdays * 24 * 60 * 60 * 1000));
        var expires = "expires="+d.toUTCString();
        document.cookie = "color=" + selectedValue + ";" + expires;
        console.log("Set cookie");
    }
}
</script>

谢谢！

Answer 1

在setColorCookie()函数中，您有一个未定义的变量exdays。