Question

我有一个下拉列表，其中包含很少的选项和按钮上的onclick事件，在从下拉列表中选择并单击按钮之后，如何将下拉列表设置为由JavaScript选择的默认值。

 <select id="userType">
              <option value="Select" disabled selected 
              id="myDefault">Select</option>
              <option value="1">Games</option>
              <option value="2">Movies</option>
           </select>
 <button type="button" name="button"onclick="addOption()">Send</button>

function addOption(){
 if (userType.value === "Select") {
    alert("Please select correct option");
 }
 else{
    console.log(userType.options[userType.selectedIndex].value);
 }
 document.getElementById('userType').value = "Select";

}

Answer 1

非常直接。只需按id选择输入，并将其值设置为默认值。

＆＃13;

function addOption(){
  // Do stuff...and then:
  document.getElementById('userType').value = "Select";

}

＆＃13;

<select id="userType">
              <option value="Select" disabled selected 
              id="myDefault">Select</option>
              <option value="1">Games</option>
              <option value="2">Movies</option>
           </select>
 <button type="button" name="button"onclick="addOption()">Send</button>

＆＃13;

Answer 2

这是您的工作代码：

$("button").click(function() {
    $('select').prop('selectedIndex', 0);
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<select id="userType">
              <option value="Select" disabled selected 
              id="myDefault">Select</option>
              <option value="1">Games</option>
              <option value="2">Movies</option>
           </select>
 <button type="button" name="button">Send</button>

Answer 3

＆＃13;

<link>

＆＃13;

试试这个

Answer 4

您可以将change事件附加到<select>元素，声明变量，将事件处理程序集变量设置为true，以验证是否发生了change事件。如果click值为<button>，则select .selectedIndex将0 Boolean属性设为true，设为Boolean到false。

＆＃13;

<script>
  var changed, select;
  function addOption() {
    if (changed) {
      select.selectedIndex = 0;
      changed = false;
    }
  }
  onload = function() {
    select = document.getElementById("userType");
    select.onchange = function() {
      changed = true;
    }

  }
</script>

<select id="userType">
              <option value="Select" disabled selected 
              id="myDefault">Select</option>
              <option value="1">Games</option>
              <option value="2">Movies</option>
           </select>
<button type="button" name="button" onclick="addOption()">Send</button>

＆＃13;

如何设置下拉列表以在javascript中的onclick事件后选择

4 个答案: