Sample: dhtmlxToolbar Two-State Button Manipulation dhtmlxToolbar main page
X
 
<script>
 
    var webBar = new dhtmlXToolbarObject("toolbarObj");
    ...
    // showing a two-state button
    webBar.showItem(itemId);
    // hiding a two-state button
    webBar.hideItem(itemId);
    // is a two-state button visible
    var isVisible = webBar.isVisible(itemId);
</script>