Sta*_*arx 97
非常简单
radiobtn = document.getElementById("theid");
radiobtn.checked = true;
gab*_*lde 32
表格
<form name="teenageMutant">
  <input value="aa" type="radio" name="ninjaTurtles"/>
  <input value="bb" type="radio" name="ninjaTurtles"/>
  <input value="cc" type="radio" name="ninjaTurtles" checked/>
</form>
默认情况下将检查value ="cc",如果删除"已选中",则在首次加载表单时将检查非框.
document.teenageMutant.ninjaTurtles[0].checked=true;
now value ="aa"被选中.其他无线电复选框未选中.
看到它在行动:http://jsfiddle.net/yaArr/
您可以使用表单ID和单选按钮ID执行相同操作.这是一个带有id的表单.
<form id="lizardPeople" name="teenageMutant">
  <input id="dinosaurs" value="aa" type="radio" name="ninjaTurtles"/>
  <input id="elephant" value="bb" type="radio" name="ninjaTurtles"/>
  <input id="dodoBird" value="cc" type="radio" name="ninjaTurtles" checked/>
</form>
默认情况下会检查value ="cc".
document.forms["lizardPeople"]["dinosaurs"].checked=true;
现在值="aa"与id ="dinosaurs"被检查,就像之前一样.
看到它在行动:http://jsfiddle.net/jPfXS/
Jus*_*son 16
香草Javascript:
yourRadioButton.checked = true;
jQuery的:
$('input[name=foo]').prop('checked', true);
要么
$("input:checkbox").val() == "true"
sbr*_*bot 11
您还可以显式设置单选按钮的值:
<form name="gendersForm">
  <input type="radio" name="gender" value="M" /> Man
  <input type="radio" name="gender" value="F" /> Woman
</form>
使用以下脚本:
document.gendersForm.gender.value="F";
并自动检查相应的单选按钮.
/**
 * setCheckedValueOfRadioButtonGroup
 * @param {html input type=radio} vRadioObj 
 * @param {the radiobutton with this value will be checked} vValue 
 */
function setCheckedValueOfRadioButtonGroup(vRadioObj, vValue) {
    var radios = document.getElementsByName(vRadioObj.name);
    for (var j = 0; j < radios.length; j++) {
        if (radios[j].value == vValue) {
            radios[j].checked = true;
            break;
        }
    }
}