Question

js获取radio属性的值

a为一个单选框的名字。
<form onsubmit="return check(this)">
<input type=radio name="a" value=0>0
<input type=radio name="a" value=1>1

function check(formObj){
var a= trim(formObj.a.value);
if(a == null || a <0){
alert("单选框未选中");
return false;
}
return true;}

我未选中单选框的任何值 ，点提交，没有弹出警告，这是为什么？

Answer 1

这样写好些吧：

<form onsubmit="return check(this);" >
<input type=radio name="a" value=0>0
<input type=radio name="a" value=1>1
<input type=submit value="提交">
</form>

<script   type="text/javascript">

function   check(formObj)
{
      for(var   i=0;i<formObj.a.length;i++)
      {         
               if(formObj.a[i].checked)
               {
               //alert("单选框选中:   "   +   formObj.a[i].value);
               return   true;
               }
      }   
      alert("单选框未选中");
      return   false;
}   

</script>

radio标签的取值方法如下：

<html:radio   property="userRole"   value="operator"   onclick="radioValue()"/>
<html:radio   property="userRole"   value="admin"   onclick="radioValue()"/>

<script   language="javascript">      
                        function   radioValue(){
                                 var   obj   =   document.all.userRole;
                                 if(obj){
                                       for(var   i=0;i<obj.length;i++){//适合length>=2时，当obj.length==null时，可以直接取obj.value值
                                             if(obj[i].checked){
                                                   alert(obj[i].value);
                                                   break;
                                             }
                                       }
                                 }         
                        }      
</script>

Answer 2

function check(formObj){
for(var i=0;i<formObj.a.length;i++){
if(formObj.a[i].checked){
alert("单选框选中: " + formObj.a[i].value);
return true;
}
}
alert("单选框未选中");
return false;}