<a href="#" onclick="collapse_menu(menu1, 0); return false">Menu 1</a><br>
<span id="menu1"></span>
<a href="#" onclick="collapse_menu(menu2, 1); return false">Menu 2</a><br>
<span id="menu2"></span>

<script language="javascript">
var on_off=new Array();
var menu_code=new Array();

number_of_menus=2;

menu_code[0]="Option 1<br>Option 2<br>Option 3<br>";
menu_code[1]="Option 1<br>Option 2<br>Option 3<br>";

for (loop=0; loop<number_of_menus; loop++){
 on_off[loop]=0;
}

function collapse_menu(menu_id, menu_number){
  if (on_off[menu_number]==0){
    menu_id.innerHTML=menu_code[menu_number];
    on_off[menu_number]=1;
  }else{
    menu_id.innerHTML="";
    on_off[menu_number]=0;
  }
}
</script>

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