<form onsubmit="return fwrite_submit(this);">
<input type="text" name=wr_subject id="wr_subject" itemname="회사명" required maxlength="120" size="120">
</form>
<script language="JavaScript" type="text/JavaScript">
function fwrite_submit(f)
{
  //글자수 검사
 if( f.wr_subject.value.length<4) {
    alert("정확한 값을 입력하세요");
    f.wr_subject.focus();
    return false;
 }

  // 한글 여부
     for (i = 0 ; i < f.wr_subject.value.length ; i++){
       var code = f.wr_subject.value.charCodeAt(i);
       var ch = f.wr_subject.value.substr(i,1).toUpperCase();
       
       code = parseInt(code);

    //한글인지 검사  
       if((ch < "0" || ch > "9")&&(ch < "A" || ch > "Z")&&((code > 255) || (code <0))) {
    }
    else {
         alert('한글만 입력 가능합니다.');
         f.wr_subject.focus();
         return false;
    }
     }
}
</script>