I am using web to lead form to enter data on a form externally. Whenever the form i submitted, leads are created in salesforce.
Now, i want to have a check for duplicates based on some fields, say first name and last name.
When the form is submitted with duplicate first name and last name, i want to show error message on the form saying that the lead exists in system.
Can you please guide me on how we can achieve this? Can we show real time error messages on web to lead form?