SPForm GetCurrentItemID on edit form

//Current web
var currentURL=GetUrlKeyValue('Source');
//Current ItemID
var CurrentItemID=GetUrlKeyValue('ID');

//Lookup field  value
var cmp=fd.field('Company').control()._el().find('select option:selected').text();

Set Value to a SingleLineText Field

fd.field('CompanyName').value(cmp);

How to set read only for field in JSeditor

fd.field('Company').readonly(true);