Triggering Action on click of button from CRM Portal website

There was a requirement to send an email to specified users(Support contacts) when user click on Submit feedback button. I was wondering if there is any way to trigger an Custom Action on click of the button on Portal Website form.

I tried with javascript emailto but it opens new outlook window for sending email, i want to send it as a background process.

If there is any alternative way to do it that would be helpful.

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