Here is the solution to implement the Confirmation popup applet (OK/Cancel) without Script in Siebel. This solution is applicable for both type of application (Standard and High Interactive application)

1. Select Applet Object
2. Create new mini button "Confirmation" under control child object
3. Add below value in HTML Attribute of the newly created control
   • onclick="if(confirm('Are you sure you want to delete this facility record along with all child details?')){}else{return false;}"

For displaying and invoking this custom button follow the basic configuration steps. After implementing this solution onbutton click system would popup 'Are you sure you want to delete this facility record along with all child details?' message with OK and Cancel option.