Perform following steps , its like a neat little trick for over ridding save functionality
- Write a custom s-control that directs the user to the standard edit page of the object in question, but sets the saveURL to point to your custom component that will perform the action. The saveURL needs to include the ID of the object.
- Override the Edit button for the object in question with your s-control.
- When the user clicks Edit, they get the standard edit page, then when they click Save, they’re redirected to your component, which performs whatever actions you need.
Read the complete hack @ Salesforce Blog