​SCRIPT5007: 정의되지 않음 또는 null 참조인 'getElementsByTagName' 속성을 가져올 수 없습니다.

파일: gnb.js, 줄: 22, 열: 4

// JavaScript Document

 this.menu = new Array();
 this.menuseq = 0;
 
 this.Start = function() {
  this.MenuBox = document.getElementById(this.DivName).getElementsByTagName("ul")[0].childNodes;
  
  // �޴��� ������ �ľ��ϴ� �κ�
  this.MenuLength = this.MenuBox.length;
  
  // �޴��� 1���� ��ũ�κп� ���콺�� Ű������ ������ �ִ� �κ�
  for ( var i=0; i<this.MenuLength; i++ ) {
   if ( this.MenuBox.item(i).tagName != "LI" ) { continue; }
   this.MenuLink = this.MenuBox.item(i).getElementsByTagName("a")[0];
   this.MenuLink.i = i;
   this.MenuLink.fnName = this.fnName;
   this.MenuLink.onmouseover = this.MenuLink.onfocus = function() { eval(this.fnName +".fnMouseOver(" + this.i + ")") }

   this.MenuSubBox = this.MenuBox.item(i).getElementsByTagName("div")[0];
   this.MenuSubMenu = this.MenuSubBox.getElementsByTagName("ul")[0].getElementsByTagName("li");
   this.MenuSubMenuLength = this.MenuSubMenu.length;
   
   // �޴��� 2���� ��ũ�κп� ���콺�� Ű������ ������ �ִ� �κ�
   for ( var j=0; j<this.MenuSubMenuLength; j++ ) {
    this.MenuSubLink = this.MenuSubMenu.item(j).getElementsByTagName("a")[0];
    this.MenuSubLink.i = i;
    this.MenuSubLink.j = j;
    this.MenuSubLink.fnName = this.fnName;
    this.MenuSubLink.onmouseover = this.MenuSubLink.onfocus = function()  { eval(this.fnName +".fnMouseSubOver(" + this.i + "," + this.j + ")") }
    this.MenuSubLink.onmouseout = this.MenuSubLink.onblur = function()  { eval(this.fnName +".fnMouseSubOut(" + this.i + "," + this.j + ")") }
   }
   
   this.MenuSubBox.style.display = "none";
   
   this.menuseq++;
   this.menu[this.menuseq] = i
  }
  
  if ( this.DefaultMenu != 0 ) {
   this.fnMouseOver(this.menu[this.DefaultMenu]);
   if ( this.DefaultSubMenu != 0 ) {
    this.fnMouseSubOver(this.menu[this.DefaultMenu],this.DefaultSubMenu - 1);
   }
  }
 }
 
 // �޴��� 1���� ��ũ�κп� ���콺�� Ű������ ������ ���� �����ϴ� �κ�
 this.fnMouseOver = function(val) {
  for ( var i=0; i<this.MenuLength; i++ ) {
   if ( this.MenuBox.item(i).tagName != "LI" ) { continue; }
   this.MenuImg = this.MenuBox.item(i).getElementsByTagName("a")[0].getElementsByTagName("img")[0];
   this.MenuSDiv = this.MenuBox.item(i).getElementsByTagName("div")[0];
   if ( i == val ) {
    this.MenuImg.src = this.MenuImg.src.replace("_off.png","_on.png");
    this.MenuSDiv.style.display = "block";
   } else {
    this.MenuImg.src = this.MenuImg.src.replace("_on.png","_off.png");
    this.MenuSDiv.style.display = "none";
   }
  }
 }
 
 // �޴��� 2���� ��ũ�κп� ���콺�� Ű������ ������ ���� �����ϴ� �κ�
 this.fnMouseSubOver = function(mnum,snum) {
  this.SubMenuImg = this.MenuBox.item(mnum).getElementsByTagName("div")[0].getElementsByTagName("ul")[0].getElementsByTagName("li")[snum].getElementsByTagName("a")[0].getElementsByTagName("img")[0];
  this.SubMenuImg.src = this.SubMenuImg.src.replace("_off.png","_on.png");
 }
 this.fnMouseSubOut = function(mnum,snum) {
  this.SubMenuImg = this.MenuBox.item(mnum).getElementsByTagName("div")[0].getElementsByTagName("ul")[0].getElementsByTagName("li")[snum].getElementsByTagName("a")[0].getElementsByTagName("img")[0];
  this.SubMenuImg.src = this.SubMenuImg.src.replace("_on.png","_off.png");
 }
 
}

해당 사항이 오류가 뜨네요.. 왜그런거죠? 작동에는 이상이 없는 것 같긴한데요..

해당 홈페이지url은 댓글로 남기겠습니다..ㅠㅠ
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