I do not find anyway that you can validate a valid url when the user enters in the standard page so I come up with this validation and I need little help to fix it.
I'm using BEGINS to see if the url starts with HTTP or HTTPs
My scenario is,
--Validation should ONLY fire when Attachment == false -- When the users enters the URL make sure the URL starts with http:// or https://
if(Attachment__c == false && NOT(ISBLANK(url__c), true (BEGINS(URL__c, "https://")))