需要幫助將函數的輸出作為輸入表單的值

Question

所以我試圖創建一個表單，將下一個星期五的日期作為值發送。 該值應采用“YYYY-MM-DD”形式

這是我到目前為止所擁有的：

<input type="hidden" name="next_charge_scheduled_at" id="s1" value="" />
<script type="text/javascript">
 var elem = document.getElementById("s1");
elem.value = function()
{
var d = new Date();

switch (d.getDay())
{
case 0: d.setDate(d.getDate() + 5);
break;

case 1: d.setDate(d.getDate() + 4);
break;

case 2: d.setDate(d.getDate() + 3);
break;

case 3: d.setDate(d.getDate() + 2);
break;

case 4: d.setDate(d.getDate() + 1);
break;

case 6: d.setDate(d.getDate() + 6);
break;
}

return d;

};
</script>

但是，就我所見，這將返回整個函數，而不是結果。

我究竟做錯了什么？

Answer 1

你已經綁定了一個函數到elem.value。如果你想把函數的結果放到elem.value，這樣做：

<input type="hidden" name="next_charge_scheduled_at" id="s1" value="" />
<script type="text/javascript">
 var elem = document.getElementById("s1");
    elem.value=getDate();

    function getDate()
    {
    var d = new Date();

    switch (d.getDay())
    {
    case 0: d.setDate(d.getDate() + 5);
    break;

    case 1: d.setDate(d.getDate() + 4);
    break;

    case 2: d.setDate(d.getDate() + 3);
    break;

    case 3: d.setDate(d.getDate() + 2);
    break;

    case 4: d.setDate(d.getDate() + 1);
    break;

    case 5: d.setDate(d.getDate() + 7);
    break;

    case 6: d.setDate(d.getDate() + 6);
    break;
    }

    return `${d.getFullYear()}-${(d.getMonth() + 1) }-${d.getDate()}`;

    };

Answer 2

您需要創建一個函數，只有當我們像calculateFriday()那樣執行函數時，我們才會得到我們將設置到輸入字段的值！

 var elem = document.getElementById("s1"); elem.value = calculateFriday(); function calculateFriday() { var d = new Date(); switch (d.getDay()) { case 0: d.setDate(d.getDate() + 5); break; case 1: d.setDate(d.getDate() + 4); break; case 2: d.setDate(d.getDate() + 3); break; case 3: d.setDate(d.getDate() + 2); break; case 4: d.setDate(d.getDate() + 1); break; case 5: d.setDate(d.getDate() + 7); break; case 6: d.setDate(d.getDate() + 6); break; } return moment(d).format('YYYY-MM-DD');; }

 <script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.24.0/moment.min.js"></script> <input type="text" tname="next_charge_scheduled_at" id="s1" value="" />