下拉列表更改事件直到第二个实例才触发

dropdown onchange event not firing until second instance

本文关键字：实例 第二个 事件 下拉列表      更新时间：2023-09-26

我遇到了最奇怪的问题，尽管我确定这很简单 - 我被难住了。 我有一个事件，它根据下拉菜单隐藏和显示div。 当我从菜单中选择一些东西时，它绝对什么都不做。 但是，如果我将其更改为第二个选择，它可以完美运行。 有人知道我搞砸了什么吗？ 感谢您的任何和所有帮助。

function call1()
{
document.getElementById("quest1").onchange = function () {
  alert("ON CHANGE FIRED");
  var val = this.options[this.selectedIndex].value;
  document.getElementById("area1z").style.display = (val == "0") ? "block" : "none";
  document.getElementById("area1a").style.display = (val == "1") ? "block" : "none";
  document.getElementById("area1b").style.display = (val == "2") ? "block" : "none";
  document.getElementById("area1c").style.display = (val == "3") ? "block" : "none";
  document.getElementById("area1d").style.display = (val == "4") ? "block" : "none";
};
}
<select id="quest1" onChange="call1()">
<option value=0></option>
<option value=1>Stretch (Maintaining a lifestyle choice for an amount of time)            </option>
<option value=2>Sum (i.e. saving money, counting workouts, etc.</option>
<option value=3>Loss (i.e. Weightloss)</option>
<option value=4>None</option>
</select>
<div id=area1z style="display:none">Please Choose a Quest</div>
<div id=area1a style="display:none">Stretch</div>
<div id=area1b style="display:none">Sum</div>
<div id=area1c style="display:none">Loss</div>
<div id=area1d style="display:none">None</div>

从以下内容中删除onChange()：

<select id="quest1" onChange="call1()">

这样写：

document.getElementById("quest1").onchange = function () {
  alert("ON CHANGE FIRED");
  var val = this.options[this.selectedIndex].value;
  document.getElementById("area1z").style.display = (val == "0") ? "block" : "none";
  document.getElementById("area1a").style.display = (val == "1") ? "block" : "none";
  document.getElementById("area1b").style.display = (val == "2") ? "block" : "none";
  document.getElementById("area1c").style.display = (val == "3") ? "block" : "none";
  document.getElementById("area1d").style.display = (val == "4") ? "block" : "none";
};

例

              <script>
                            function call1()
                        {
                          alert("ON CHANGE FIRED");
                          var val=document.getElementById("quest1").value;
                          alert(val);
                          document.getElementById("area1z").style.display = (val == "0") ? "block" : "none";
                          document.getElementById("area1a").style.display = (val == "1") ? "block" : "none";
                          document.getElementById("area1b").style.display = (val == "2") ? "block" : "none";
                          document.getElementById("area1c").style.display = (val == "3") ? "block" : "none";
                          document.getElementById("area1d").style.display = (val == "4") ? "block" : "none";
                        }
                        </script>
                        <select id="quest1" onChange="call1()">
                        <option value="0"></option>
                        <option value="1">Stretch (Maintaining a lifestyle choice for an amount of time)            </option>
                        <option value="2">Sum (i.e. saving money, counting workouts, etc.</option>
                        <option value="3">Loss (i.e. Weightloss)</option>
                        <option value="4">None</option>
                        </select>
                        <div id="area1z" style="display:none">Please Choose a Quest</div>
                        <div id="area1a" style="display:none">Stretch</div>
                        <div id="area1b" style="display:none">Sum</div>
                        <div id="area1c" style="display:none">Loss</div>
                        <div id="area1d" style="display:none">None</div>

这是您正在尝试做的演示。

要么

从代码中删除"onchaange"，要么删除"document.getElementById（"quest1"）.onchange = function （） {}"。

document.getElementById("quest1").onchange = function () {
  alert("ON CHANGE FIRED");
    var val = this.options[this.selectedIndex].value;
    document.getElementById("area1z").style.display = (val == "0") ? "block" : "none";
    document.getElementById("area1a").style.display = (val == "1") ? "block" : "none";
    document.getElementById("area1b").style.display = (val == "2") ? "block" : "none";
    document.getElementById("area1c").style.display = (val == "3") ? "block" : "none";
    document.getElementById("area1d").style.display = (val == "4") ? "block" : "none";
  };

JSFIDDLE 链接：http://jsfiddle.net/2M74g/1/

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