public function field_get($type,$com=''){
		if(empty($com)){
			$fn=BLIBRARIESFRAMEWORKPATH.'mvc'.DIRECTORY_SEPARATOR.'field'.DIRECTORY_SEPARATOR.$type.'.php';
			$class='BControllerField_'.$type;
			} else {
			$fn=BCOMPONENTSAPPLICATIONPATH.$com.DIRECTORY_SEPARATOR.'fields'.DIRECTORY_SEPARATOR.$type.'.php';
			if(!file_exists($fn)){
				$fn=BCOMPONENTSFRAMEWORKPATH.$com.DIRECTORY_SEPARATOR.'fields'.DIRECTORY_SEPARATOR.$type.'.php';
				}
			$class='BControllerField_'.$com.'_'.$type;
			}
		if(!file_exists($fn)){
			if(DEBUG_MODE){
				BDebug::error('File "'.$fn.'" does not exist! type='.$type.', com='.$com);
				}
			return NULL;
			}
		require_once($fn);
		$field=new $class;
		$field->controller=$this;
		$field->com=$com;
		return $field;
		}