表单

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

这个脚本

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

小提琴:http://jsfiddle.net/PNpUS/

下面是扩展后的解决方案，即不继续提交，并在未选中单选按钮时发送警报。当然，这意味着你必须在一开始就不检查它们!

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

只要记住在每个单选按钮的表单中设置id ('radio1'，'radio2'或任何你叫它的名字)，否则脚本将无法工作。

只是对马克·比克做了一点点修改;

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代码来检查单选按钮是否被选中

<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>

给单选按钮，相同的名称，但不同的id。

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;
   }
}

一种简单的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;       
    }
}

http://www.somacon.com/p143.php/

function 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 "";
}