如何检查是否使用JavaScript选择了单选按钮？

我在HTML表单中有两个单选按钮。当其中一个字段为空时，将出现一个对话框。如何检查是否选中了单选按钮？

让我们假设您有这样的HTML

<input type="radio" name="gender" id="gender_Male" value="Male" />
<input type="radio" name="gender" id="gender_Female" value="Female" />

根据标记的确切性质，可以使上述内容更有效，但这应该足以让您开始

---

如果您只是想查看页面上的任何地方是否选择了any单选按钮，这会使操作变得非常简单

如果在页面的某个位置至少选择了一个单选按钮，则此函数将返回true。同样，这可能需要根据您的特定HTML进行调整

function atLeastOneRadio() {
    return ($('input[type=radio]:checked').size() > 0);
}

---

对于服务器端验证（请记住，您不能完全依赖Javascript进行验证！），这取决于您选择的语言，但您只需检查请求字符串的

gender

值

if ($('input[name=gender]:checked').length > 0) {
    // do something here
}

让我把它分解成几部分，以便更清楚地描述它。 jQuery从左到右处理事务

input[name=gender]:checked

将其限制为输入标记

将其限制为上一个组中具有名称性别的标记

将其限制为在上一组中选择的复选框/单选按钮

---

如果要完全避免这种情况，请在HTML代码中将其中一个单选按钮标记为选中（

checked=“checked”

），这将保证始终选择一个单选按钮。

一种普通的JavaScript方式

var radios = document.getElementsByTagName('input');
var value;
for (var i = 0; i < radios.length; i++) {
    if (radios[i].type === 'radio' && radios[i].checked) {
        // get value, set checked flag or do whatever you need to
        value = radios[i].value;       
    }
}

var radios=document.getElementsByTagName（'input'）；
var值；
对于（变量i=0；i

只是对马克·比克稍加修改

HTML代码

<form name="frm1" action="" method="post">
  <input type="radio" name="gender" id="gender_Male" value="Male" />
  <input type="radio" name="gender" id="gender_Female" value="Female" / >
  <input type="button" value="test"  onclick="check1();"/>
</form>

和Javascript代码来检查是否选中了单选按钮

<script type="text/javascript">
    function check1() {            
        var radio_check_val = "";
        for (i = 0; i < document.getElementsByName('gender').length; i++) {
            if (document.getElementsByName('gender')[i].checked) {
                alert("this radio button was clicked: " + document.getElementsByName('gender')[i].value);
                radio_check_val = document.getElementsByName('gender')[i].value;        
            }        
        }
        if (radio_check_val === "")
        {
            alert("please select radio button");
        }        
    }
</script>

函数check1（）{
var无线电检查_val=“”；
对于（i=0；i

HTML代码

<input type="radio" name="offline_payment_method" value="Cheque" >
<input type="radio" name="offline_payment_method" value="Wire Transfer" >

Javascript代码：

var off_payment_method=document.getElementsByName（'offline_payment_method'）；
var ischecked_method=false；
对于（变量i=0；i

函数getCheckedValue（radioObj）{ 如果（！radioObj） 返回“”； var radioLength=radioObj.长度； 如果（放射长度==未定义） 如果（无线电目标检查） 返回radioObj.value； 其他的 返回“”； 对于（var i=0；i这是我为解决此问题而创建的实用函数

    //define radio buttons, each with a common 'name' and distinct 'id'. 
    //       eg- <input type="radio" name="storageGroup" id="localStorage">
    //           <input type="radio" name="storageGroup" id="sessionStorage">
    //param-sGroupName: 'name' of the group. eg- "storageGroup"
    //return: 'id' of the checked radioButton. eg- "localStorage"
    //return: can be 'undefined'- be sure to check for that
    function checkedRadioBtn(sGroupName)
    {   
        var group = document.getElementsByName(sGroupName);

        for ( var i = 0; i < group.length; i++) {
            if (group.item(i).checked) {
                return group.item(i).id;
            } else if (group[0].type !== 'radio') {
                //if you find any in the group not a radio button return null
                return null;
            }
        }
    }

//定义单选按钮，每个按钮都有一个通用的“名称”和不同的“id”。
//例如
//           
//参数sGroupName：组的“名称”。例如，“存储组”
//返回选中单选按钮的“id”。例如“本地存储”
//返回：可以是“未定义的”-请务必检查是否存在此问题
函数checkedRadiobN（sGroupName）
{   
var group=document.getElementsByName（sGroupName）；
对于（变量i=0；i

本页中的脚本帮助我想出了下面的脚本，我认为它更完整、更通用。基本上，它将验证表单中任意数量的单选按钮，这意味着它将确保为表单中的每个不同单选组选择了一个单选选项。e、 g在以下测试表格中：

   <form id="FormID">

    Yes <input type="radio" name="test1" value="Yes">
    No <input type="radio" name="test1" value="No">

    <br><br>

    Yes <input type="radio" name="test2" value="Yes">
    No <input type="radio" name="test2" value="No">

   <input type="submit" onclick="return RadioValidator();">

对
不



对
不

RadioValidator脚本将确保在提交之前已给出“test1”和“test2”的答案。表单中可以有任意多个广播组，它将忽略任何其他表单元素。所有缺失的无线电应答将显示在单个警报弹出窗口中。就这样，我希望它能帮助人们。任何错误修复或有用的修改（欢迎：）

函数RadioValidator（）
{
var showart=''；
var AllFormElements=window.document.getElementById（“FormID”）.elements；
对于（i=0；ifunction getCheckedValue(radioObj) {
    if(!radioObj)
        return "";
    var radioLength = radioObj.length;
    if(radioLength == undefined)
        if(radioObj.checked)
            return radioObj.value;
        else
            return "";
    for(var i = 0; i < radioLength; i++) {
        if(radioObj[i].checked) {
            return radioObj[i].value;
        }
    }
    return "";
}

    //define radio buttons, each with a common 'name' and distinct 'id'. 
    //       eg- <input type="radio" name="storageGroup" id="localStorage">
    //           <input type="radio" name="storageGroup" id="sessionStorage">
    //param-sGroupName: 'name' of the group. eg- "storageGroup"
    //return: 'id' of the checked radioButton. eg- "localStorage"
    //return: can be 'undefined'- be sure to check for that
    function checkedRadioBtn(sGroupName)
    {   
        var group = document.getElementsByName(sGroupName);

        for ( var i = 0; i < group.length; i++) {
            if (group.item(i).checked) {
                return group.item(i).id;
            } else if (group[0].type !== 'radio') {
                //if you find any in the group not a radio button return null
                return null;
            }
        }
    }

   <form id="FormID">

    Yes <input type="radio" name="test1" value="Yes">
    No <input type="radio" name="test1" value="No">

    <br><br>

    Yes <input type="radio" name="test2" value="Yes">
    No <input type="radio" name="test2" value="No">

   <input type="submit" onclick="return RadioValidator();">

<SCRIPT LANGUAGE="JAVASCRIPT">
function RadioValidator()
{
    var ShowAlert = '';
    var AllFormElements = window.document.getElementById("FormID").elements;
    for (i = 0; i < AllFormElements.length; i++) 
    {
        if (AllFormElements[i].type == 'radio') 
        {
            var ThisRadio = AllFormElements[i].name;
            var ThisChecked = 'No';
            var AllRadioOptions = document.getElementsByName(ThisRadio);
            for (x = 0; x < AllRadioOptions.length; x++)
            {
                 if (AllRadioOptions[x].checked && ThisChecked == 'No')
                 {
                     ThisChecked = 'Yes';
                     break;
                 } 
            }   
            var AlreadySearched = ShowAlert.indexOf(ThisRadio);
            if (ThisChecked == 'No' && AlreadySearched == -1)
            {
            ShowAlert = ShowAlert + ThisRadio + ' radio button must be answered\n';
            }     
        }
    }
    if (ShowAlert != '')
    {
    alert(ShowAlert);
    return false;
    }
    else
    {
    return true;
    }
}
</SCRIPT>

<input type="radio" name="gender_male" value="Male" />
<input type="radio" name="gender_female" value="Female" />

if ($("#gender_male").attr("checked") == true) {
...
}

if(document.getElementById('radio1').checked) {
} else if(document.getElementById('radio2').checked) {
} else {
  alert ("You must select a button");
  return false;
}

if (!checkRadioArray(document.ExamEntry.level)) { 
    msg+="What is your level of entry? \n"; 
    document.getElementById('entry').style.color="red"; 
    result = false; 
} 

if(msg==""){ 
    return result;  
} 
else{ 
    alert(msg) 
    return result;
} 

function Radio() { 
    var level = radio.value; 
    alert("Your level is: " + level + " \nIf this is not the level your taking then please choose another.") 
} 

function checkRadioArray(radioButtons) { 
    for(var r=0;r < radioButtons.length; r++) { 
        if (radioButtons[r].checked) { 
            return true; 
        } 
    } 
    return false; 
} 

<form name="teenageMutant">
  <input type="radio" name="ninjaTurtles"/>
</form>

if(!document.teenageMutant.ninjaTurtles.checked){
  alert('get down');
}

var verified1 = $('#SOME_ELEMENT1').val();
var verified2 = $('#SOME_ELEMENT2').val();
var final_answer = null;
if( $('#SOME_ELEMENT1').attr('checked') == 'checked' ){
  //condition
  final_answer = verified1;
}
else
{
  if($('#SOME_ELEMENT2').attr('checked') == 'checked'){
    //condition
    final_answer = verified2;
   }
   else
   {
     return false;
   }
}

// html
<input name="gender" type="radio" value="M" /> Male <input name="gender" type="radio" value="F" /> Female

// gender (required)
var gender_check = $('input:radio[name=gender]:checked').val();
if ( !gender_check ) {
    alert("Please select your gender.");
    return false;
}

<form id="myForm">
<label>Who will be left?
  <label><input type="radio" name="output" value="knight" />Kurgan</label>
  <label><input type="radio" name="output" value="highlander" checked />Connor</label>
</label>
</form>

<script>
function getSelectedRadioValue (formElement, radioName) {
    return ([].slice.call(formElement[radioName]).filter(function (radio) {
        return radio.checked;
    }).pop() || {}).value;
}

var formEl = document.getElementById('myForm');
alert(
   getSelectedRadioValue(formEl, 'output') // 'highlander'
)
</script>

$('input[name="myRadio"]').change(function(e) { // Select the radio input group

    // This returns the value of the checked radio button
    // which triggered the event.
    console.log( $(this).val() ); 

    // but this will return the first radio button's value,
    // regardless of checked state of the radio group.
    console.log( $('input[name="myRadio"]').val() ); 

});

var x = Array.prototype.filter.call(document.getElementsByName('checkThing'), function(x) { return x.checked })[0];

var x = Array.prototype.filter.call(document.getElementsByName('checkThing'), function(x) { return x.checked });

<input type="radio" name="radiosname" value="1" />
<input type="radio" name="radiosname" value="2" id="radiowithval2"/>
<input type="radio" name="radiosname" value="3" />

// Check if second radio is selected (by id)
if ($('radiowithval2').get("checked"))

// Check if third radio is selected (by name and value)
if ($$('input[name=radiosname][value=3]:checked').length == 1)


// Check if something in radio group is choosen
if ($$('input[name=radiosname]:checked').length > 0)


// Set second button selected (by id)
$("radiowithval2").set("checked", true)

var radios = document.querySelectorAll('input[type="radio"]:checked');
var value = radios.length>0? radios[0].value: null;

if(!document.yourformname.yourradioname[0].checked 
   && !document.yourformname.yourradioname[1].checked){
    alert('is this working for all?');
    return false;
}

if(document.querySelectorAll('input[type="radio"][name="name_of_radio"]:checked').length < 1)

<label class="block"><input type="radio" name="calculation" value="add">+</label>
<label class="block"><input type="radio" name="calculation" value="sub">-</label>
<label class="block"><input type="radio" name="calculation" value="mul">*</label>
<label class="block"><input type="radio" name="calculation" value="div">/</label>

<p id="result"></p>

var options = document.getElementsByName("calculation");

for (var i = 0; i < options.length; i++) {
    if (options[i].checked) {
        // do whatever you want with the checked radio
        var calc = options[i].value;
        }
    }
    if(typeof calc == "undefined"){
        document.getElementById("result").innerHTML = " select the operation you want to perform";
        return false;
}

var checked_gender = document.querySelector('input[name = "gender"]:checked');

if(checked_gender != null){  //Test if something was checked
alert(checked_gender.value); //Alert the value of the checked.
} else {
alert('Nothing checked'); //Alert, nothing was checked.
}

<input type="radio" name="status" id="marriedId" value="Married" />
<input type="radio" name="status" id="divorcedId" value="Divorced" />

let htmlNodes = document.getElementsByName('status');

let radioButtonsArray = Array.from(htmlNodes);

let isAnyRadioButtonChecked = radioButtonsArray.some(element => element.checked);

  Array.from(document.getElementsByClassName("className")).filter(x=>x['checked']);

[...myForm.sex].filter(r=>r.checked)[0].value