CRM Form Customization JavaScript

SAVE and Close Function
Save  -  Xrm.Page.data.entity.save();
Save &  Close  -  Xrm.Page.data.entity.save("saveandclose");
Save &  New  -  Xrm.Page.data.entity.save("saveandnew");
 Close - Xrm.Page.ui.close();

dns_JavaScript/Food.js
Read text box value

Xrm.Page.data.entity.attributes.get("dnsb_foodreason").getValue();
var fName = Xrm.Page.data.entity.attributes.get("fName").getValue();
check value is null or not
if (fName==null) fName = "";

Get html element value

var plFS = document.getElementById("dns_foodstatus");