Tab Diasable/Enable using javascript

Hi,

I am trying to disable/enable an Item's tab based on its classification. I created OnChange event for classification field on item's form and added the following code:

top.Tab = function ()
{
  if (!parent.relationships)
  {
    setTimeout("top.Tab();", 100);
    return;
  }
   var rel_tabs = "Cleaning Activities"; // Relationship Name
    var tabsIds = top.aras.getRelationshipTypeId(rel_tabs);
 
    if (parent.relationships.document.readyState != "complete" || !parent.relationships.currTabID)
  {setTimeout("top.Tab();", 100); }
  else
  {
      var recp_tabs = tabsIds; 
      var recp_type = parent.item.selectSingleNode("classification");
      if (recp_type)
      {
        recp_type = recp_type.text;
          alert(recp_type);
      if(recp_type.indexOf("Cleaning") > -1)
        {
             parent.relationships.document.relTabbar.setTabEnabled(tabsIds, 1);
           
        }
        else
        { 
         parent.relationships.document.relTabbar.setTabEnabled(tabsIds, 0);
         }
 
      }
    }
 
};

setTimeout("top.Tab()", 200);

I found this code in a Form Event of ItemType's form.

This is not working, I am not facing any errors but it is not disabling the tab if I select other classification type. I am using Innovator 10.0

Any issues with my code? Please help me.