jQuery로 폼 체크해서 없으면
http://codepen.io/eond/pen/dYypOZ

javascript로 삽질
http://codepen.io/eond/pen/qOBNwq

원본 참조..
http://codepen.io/eond/pen/EVxyMV

Form
http://api.jquery.com/category/forms/

Form > focusout()
http://api.jquery.com/focusout/
http://www.w3schools.com/jquery/event_focusout.asp
http://www.w3schools.com/jquery/tryit.asp?filename=tryjquery_event_focusout

Form > blur()
http://www.w3schools.com/jquery/tryit.asp?filename=tryjquery_event_blur_alert

javascript - onblur, onfocusout
http://blog.naver.com/ksh81850/220326749715

jQuery 마우스 이벤트
http://www.nextree.co.kr/p10008/

jQuery keyup *제이쿼리 관련 자료가 많음.
http://blog.naver.com/gmlwns77/50158666446

jquery input value