[javascript] jQuery / Javascript code check, if not undefined

Is this code good?

var wlocation = $(this).closest('.myclass').find('li a').attr('href');
if (wlocation.prop !== undefined) { window.location = wlocation; }

or should I do

var wlocation = $(this).closest('.myclass').find('li a').attr('href');
if (wlocation.prop !== "undefined") { window.location = wlocation; }

$.fn.attr(attributeName) returns the attribute value as string, or undefined when the attribute is not present.

Since "", and undefined are both falsy (evaluates to false when coerced to boolean) values in JavaScript, in this case I would write the check as below:

if (wlocation) { ... }

I generally like the shorthand version:

if (!!wlocation) { window.location = wlocation; }