You cannot do this since the content is coming via an iframe of another domain http://mappedinny.com/
<iframe src="http://mappedinny.com/" height="900" width="100%%" frameborder="0" scrolling="no"></iframe>
This is the error you should be getting when you try to access
$('iframe').contents().find('li[data-hiringurl]').val()
SecurityError: Failed to read the 'contentDocument' property from 'HTMLIFrameElement': Blocked a frame with origin "http://wearemadeinny.com" from accessing a cross-origin frame.
Update:
If this for your own web-scraping purpose try disabling same origin policy in your browser configuration. Here are the links which will help you to disable same origin policy
Chrome: Disable same origin policy in Chrome
Firefox: Disable firefox same origin policy