CRM 2011 Javascript Cancelling Onsave Event

*Note make sure you have a parameter defined to receive the Execution Object Javascript Eg. function EitherOne(executionObj) {     var Field1 = Xrm.Page.data.entity.attributes.get("customerid").getValue();     var Field2 = Xrm.Page.data.entity.attributes.get("vw_name").getValue();     if (Field1 == null && Field2 == null) {         alert('Either Customer or Name fields need to be entered with data.');         // The getEventArgs() method returns an object with methods to manage the Save event.         // The preventDefault() method cancels the save operation        executionObj.getEventArgs().preventDefault();         Xrm.Page.ui.controls.get("customerid").setFocus();     }     else { onSave(); } } End of Script Where to place the script? *Note Make sure u check the pass execution context as first parameter.