询问关于单选框的验证问题 - V2EX

<SCRIPT LANGUAGE="JavaScript">
function check(form) {
var checkit = true
for (var i=0;i<form.sel.length;i++) {
form.sel[i].checked?checkit=true:checkit=false;
}
if (checkit) {return true} else {alert("please select one");return false}
}
</SCRIPT>
<form name="form1" onsubmit="return check(this)">
<input name="sel" type="radio" value="selA">A
<input name="sel" type="radio" value="selB">B
<input name="sel" type="radio" value="selC">C
<INPUT TYPE="submit" VALUE="submit">
</form>