New Post: Perform client side validation on Enhanced Rich Text box

I want to perform client side validation(Required) on Enhanced Rich text box. I am reading the value as suggested in post:
http://sympmarc.com/2013/09/11/setting-a-rich-text-column-in-a-sharepoint-form-with-jquery-sharepoint-2010/

initially when the ERTB is blank .html() returns 'Undefined'. even after entering some text it returns 'Undefined'. Is it browser specific issue? I am using IE. please suggest any workaround for this..