Enable Disable toolbar element

Dear Support Team!

I would like enable or disable element from script.

var toolbar = new dhtmlXToolbarObject("toolbarObj_<?php echo $ID;?>");
toolbar.attachEvent("onClick",parent.dba.tab_toolbar_click);
toolbar.setIconsPath("/infobase_web/dhtmlx/toolbar/img/");
toolbar.loadXML("<?php echo base_url();?>/index.php/toolbarxml/toolbar_xml/iktatas_form");

if(document.getElementById('iktatoszam<?php echo $ID;?>').value != " ")
{
  toolbar.enableItem('partner'); 
  toolbar.enableItem('scan');
}

error on run: this.objPull[itemId] is undefined

What’s wrong?

Tahnk you for your help

loadXML loads data asynchronously. Therefore, methods that applied to certain nodes should be called from loading end handler:

toolbar.loadXML("<?php echo base_url();?>/index.php/toolbarxml/toolbar_xml/iktatas_form",doAfterLoading);

function doAfterLoading(){
if(document.getElementById(‘iktatoszam<?php echo $ID;?>’).value != " ")
{
toolbar.enableItem(‘partner’);
toolbar.enableItem(‘scan’);
}
}