baclight/app/javascript/controllers/add_network_exception_controller.js

import { Controller } from "@hotwired/stimulus"

export default class extends Controller {
    static targets = ["template", "container"]

    connect() {
        console.log("connect")
    }

    add(event) {
        console.log("start")
        event.preventDefault()
        event.stopPropagation()

        const content = this.templateTarget.innerHTML.replace(/NEW_EXC_RECORD/g, new Date().getTime())

        this.containerTarget.insertAdjacentHTML("beforeend", content)
        console.log("end")
    }
}