주민번호 입력 object 유효성 체크

//---------------------------------------------------------------------------------------------------------------------------------
// 주민번호 입력 object 유효성 체크
//---------------------------------------------------------------------------------------------------------------------------------
function keydown_jumin(jumin, e){

    if (n) {  var nKey = e.which; }
    if (ie) { var ieKey = e.keyCode; }
    if (nKey ==08 || ieKey ==08) {   /*벡스페이스==08를 칠경우 */ return true;}

    del_dot_replace(jumin);
    var str =jumin.value;
    var temp="";
    for(i=0;i<str.length;i++) {
        if(is_jumin_num(str.substring(i,i+1))){
            temp=temp+str.substring(i,i+1)
        }
    }
    str=temp;

    if(str.length<6) {jumin.value=str; return true;}
    else {
        jumin.value=str.substring(0,6)+'-'+str.substring(6,13);
    }
    return true;
}