使用JavaScript不工作的HTML选择

Question

请检查一下开关语句

只有默认选项才能工作。

case x="Fin"和case x="Intercom"不起作用。不知道为什么。谢谢!

代码：

    <p>Niche</p>
        <select name="niche" id="niche" onchange="FCM_niche()">
            <option value="empty" selected="">Select Niche</option>
            <option value="fin">FIN</option>
            <option value="intercom">Intercom</option>
        </select>

    <script type="text/javascript">
                function FCM_niche() {
                    var x = document.getElementById("niche").value;
                   switch (true) {
                        case x="FIN":
                           document.getElementById("FCM_select_niche").innerHTML = "FFFF";
                           break;
                        case x="Intercom":
                           document.getElementById("FCM_select_niche").innerHTML = "IIII";
                           break;
                        default:
                           document.getElementById("FCM_select_niche").innerHTML = "DDDD";
                      }
                };
            </script>
<div id="FCM_select_niche">        
</div>

Answer 1

请看一下这个JS小提琴，显示您代码的工作版本：https://jsfiddle.net/jspruance/ebjnqt2r/

只要对你的JS做一些小的调整，你就应该开始运行了。

1)把开关语句建立在'x‘变量上：' switch (x)’

2)根据选定的值(而不是显示的文本)计算每一种情况: ex: case "fin“

function FCM_niche() {
    var x = document.getElementById("niche").value;

    switch(x) {
        case "fin":
            document.getElementById("FCM_select_niche").innerHTML = "FFFF";
            break;
        case "intercom":
            document.getElementById("FCM_select_niche").innerHTML = "IIII";
            break;
        default:
            document.getElementById("FCM_select_niche").innerHTML =       "DDDD";
    }
};

这应该会给trick...good带来好运。

Answer 2

您的开关语句无效。此外，您还在对照选定的文本检查开关大小写，而不是值。

    <p>Niche</p>
        <select name="niche" id="niche" onchange="FCM_niche()">
            <option value="empty" selected="">Select Niche</option>
            <option value="fin">FIN</option>
            <option value="intercom">Intercom</option>
        </select>

    <script type="text/javascript">
                function FCM_niche() {
                    var x = document.getElementById("niche").value;
                   switch (x) {
                        case "fin":
                           document.getElementById("FCM_select_niche").innerHTML = "FFFF";
                           break;
                        case "intercom":
                           document.getElementById("FCM_select_niche").innerHTML = "IIII";
                           break;
                        default:
                           document.getElementById("FCM_select_niche").innerHTML = "DDDD";
                      }
                };
            </script>
<div id="FCM_select_niche">        
</div>

​

Answer 3

var x = document.getElementById("niche").value;
switch (x) {
  case "FIN":
    document.getElementById("FCM_select_niche").innerHTML = "FFFF";
    break;
  case "Intercom":
    document.getElementById("FCM_select_niche").innerHTML = "IIII";
    break;
  default:
    document.getElementById("FCM_select_niche").innerHTML = "DDDD";
}