How can i override save button call?

class newActivity
{     
     function newActivity($bean, $event, $arguments)
     {
               
               

if($bean->create_new_activity_c == 0 &&  $bean->parent_type == "Projects" && ($bean->status=="Held" || $bean->status=="Complete"))
               {   
                    $projectBean = BeanFactory::getBean("Projects",$bean->parent_id , array('disable_row_level_security' => true));//get account bean
                         
               if($projectBean->status_c != 'Completed' && $projectBean->status_c != 'Cancelled' && $projectBean->status_c != 'No_prospects' )
                    {
                       $accountBean = BeanFactory::getBean("Accounts",$bean->account_id_c , array('disable_row_level_security' => true));//get account bean
                       
                       $newActivity = BeanFactory::newBean($bean->next_activity_type_c);//create new activity bean
                       $newActivity->name=$accountBean->name;
                       $newActivity->date_start=$bean->next_activiti_date_c;
                       $newActivity->description=$bean->next_activity_desc_c;
                       $newActivity->save();
                      
                       $bean->new_call_id_c=$bean->next_activity_type_c.'/'.$newActivity->id.'/edit';//here i am saving the new record edit view
                       $bean->create_new_activity_c=1;//changing it to one so that the logichook doesnt execute  //  multiple times
                      }
                    
            }
           
                }
}

      _saveModel: function() {
             
          var url ="";
          JSON.stringify(this.model,function(key,value){
          url=value.new_call_id_c;
          console.log("1 "+url);
          });
             
             
             
        var options,
            successCallback = _.bind(function() {
                // Loop through the visible subpanels and have them sync. This is to update any related
                // fields to the record that may have been changed on the server on save.
                _.each(this.context.children, function(child) {
                    if (child.get('isSubpanel') && !child.get('hidden')) {
                        child.get('collapsed') ? child.resetLoadFlag(false) : child.reloadData({recursive: false});
                        if(!_.isEmpty(url))
                        {
                                   console.log("2 "+url);
                                   App.router.navigate(url, {trigger: true});
                              }
                    }
                });
                if (this.createMode) {
                         console.log("3 "+url);
                    app.navigate(this.context, this.model);
                } else if (!this.disposed && !app.acl.hasAccessToModel('edit', this.model)) {
                    //re-render the view if the user does not have edit access after save.
                    console.log("4 "+url);
                    this.render();
                }
            }, this);

        //Call editable to turn off key and mouse events before fields are disposed (SP-1873)
        this.turnOffEvents(this.fields);

        options = {
            showAlerts: true,
            success: successCallback,
            error: _.bind(function(error) {
                if (error.status === 412 && !error.request.metadataRetry) {
                    this.handleMetadataSyncError(error);
                    console.log("5 "+url);
                } else if (error.status === 409) {
                    app.utils.resolve409Conflict(error, this.model, _.bind(function(model, isDatabaseData) {
                        if (model) {
                            if (isDatabaseData) {
                                         console.log("6 "+url);
                                successCallback();
                            } else {
                                         console.log("7 "+url);
                                this._saveModel();
                            }
                        }
                    }, this));
                } else if (error.status === 403 || error.status === 404) {
                    this.alerts.showNoAccessError.call(this);
                     console.log("8 "+url);
                } else {
                    this.editClicked();
                    console.log("9 "+url);
                }
            }, this),
            lastModified: this.model.get('date_modified'),
            viewed: true
        };

        options = _.extend({}, options, this.getCustomSaveOptions(options));

        this.model.save({}, options);
    },