배열 폼 radio 폼 자바스크립트 검사

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var school_a = document.getElementsByName("school_a[]"); 
 
      if(school_a[0].value=="")
   {
         alert("  입력해 주십시오 ");
          school_a[0].focus();
    return false;
   }
 
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<input type=text name=school_a[]  size="15" class="input02">
<input type=text name=school_a[]  size="15" class="input02">
<input type=text name=school_a[]  size="15" class="input02">
<input type=text name=school_a[]  size="15" class="input02">
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if(formObj.m_onoff[0].checked==false && formObj.m_onoff[1].checked==false){
      alert('회원 발신 메일수신 여부를 선택해 주십시오 ');
      return false;
    }
 
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<input type="radio"  name="m_onoff" value="2">예, 받겠습니다.&nbsp;&nbsp;
                  <input type="radio"  name="m_onoff" value="1">아니오, 괜찮습니다.