A form, by definition, has to result in some form of action. You can go hog wild designing forms, but at the end of the day it all has to go somewhere. The action can be php or js or direct-to-email (this seems foolhardy to me). If you're uneasy about php, why not stick with a <mailto> link?
I wouldn't try anything client side. There are services both free and paid that will process forms for you on an externally hosted PHP platform. Its also worth checking if your hosting service provides a free PHP form script.
I first used a third party form supplier which was simplicity itself to set up. They seem to have some filtering as I have never had bot generated spam through that form which I still use.
My ISP provides free hosting without PHP but they do give access to a form mail script. I have a small hobby site with them but I can't remember anybody ever using the form (memo to self, check that it still works).
My main site uses PHP for email contact but I have a free script which I installed before I learned any PHP. Again it was simple to set up, no knowledge of PHP was necessary. I do get some automated spam through those forms, it was quite a nuisance until I blocked all Russian IP addresses.