we currently have a contact us page that allows visitors to send an email to us through it, would it be a good idea to also send an email to the visitor thanking him for the message to let him know it was sent?
As far as you showing an alert with a thank you message on submit of form no need to send an email.
Reasons: 1- Email gets ignored 2- I personally don't like to receive an email for a thank you message 3- you need to develop a mail template which can increase time and cost.
You can send a reply email based on the query submitted by the client and in that you can add a Thank you message.
A follow up email may be considered spam, but as others have said, you should provide feedback as to the state of the action within your site.
Some suggestions for the feedback:
- The feedback should inform the user what happened (e.g. an email was sent to us, and probably thank them for their time/effort)
- The feedback should set the users expectation (e.g. you will receive a reply within 24 hours)
- The feedback should let to user what to do next (e.g. Go back to their task, display a relevant CTA etc)
There's probably more, but those would be a good start.
In-page feedback and thank you message is absolutely necessary.
Regarding a possible email, rather than a thank you note, you could let the user decide if they want to receive a copy of their message at their email address. It's both a confirmation that their message has been sent and a copy for their own record that they might find useful (depending on the type of website and message they send).