javascript - 带有 "other"(必需)文本选项的 HTML 单选输入

Question

我有一组带有文本字段的“其他”选项的 radio 输入。我的问题是如何在选择其他选项时使文本字段成为必填项。

到目前为止我想出的代码::

<form method="POST" action="testPage.php">
  <input type="radio" name="option" value="1">Option 1<br>
  <input type="radio" name="option" value="2">Option 2<br>
  <input type="radio" name="option" value="3">Option 3<br>
  <input type="radio" name="option" value="">Other 
  <input type="text" name="othertext" onchange="changeradioother()">
  <input type="submit" value="Submit">
</form>

<script>

  function changeradioother(){
  var other= document.getElementById("other");
  other.value=document.getElementById("inputother").value;
  }

</script>

Answer 1

尝试在单击其他单选按钮时调用函数以将输入字段设置为必填:

<script>

function changeradioother(){
	  var other= document.getElementById("other");
	  other.value=document.getElementById("inputother").value;
	  }
function setRequired(){

	document.getElementById("inputother").required=true;
}

function removeRequired(){
if(document.getElementById("inputother").required == true){
	document.getElementById("inputother").required=false;
}
}
</script>

<form method="POST" action="testPage.php">
  <input type="radio" name="option" value="1" onclick="removeRequired();">Option 1<br>
  <input type="radio" name="option" value="2" onclick="removeRequired();">Option 2<br>
  <input type="radio" name="option" value="3" onclick="removeRequired();">Option 3<br>
  <input type="radio" name="option" value="" onclick="setRequired();" id="other">Other 
  <input id="inputother" type="text" name="othertext" onchange="changeradioother()">
  <input type="submit" value="Submit">
</form>