How can I tell if a variable is wrapped in jQuery or not?

I have a function that has the signature of:

function(id,target){
 //do stuff
}

The target parameter is assumed to be a jQuery wrapped object however it is possible that it could be a dom element in which 开发者_开发知识库case I'd like to wrap it in jQuery before I do operations on it. How can I test the target variable for jQuery?

if(!(target instanceof jQuery)) {
  target = jQuery(target);
} 

You can use instanceof

obj instanceof jQuery

Check if object is a jQuery object