<input type='checkbox' value='眼部' name='s_selftesting_buwei[]'>眼部
<input type='checkbox' value='耳部' name='s_selftesting_buwei[]'>耳部
if($("input[name='s_selftesting_buwei[]']").is(':checked')==false){
lert("请选您的症状出现部位");
$("input[name='s_selftesting_buwei[]']").focus();
return false;
}
<input type='radio' value='15-25岁' name='s_selftesting_agelong'>15-25岁
<input type='radio' value='25-35岁' name='s_selftesting_agelong'>25-35岁
var val=$('input:radio[name="s_selftesting_agelong"]:checked').val();
if(val==null){
alert("请选择您现在处于哪个年龄段");
$('input:radio[name="s_selftesting_agelong"]').focus();
return false;
}