finish.style.visibility = 'hidden'
        this.container.appendChild(finish)
        // Appends dynamically loaded lines to existing line elements.
        this.lines = [...this.container.querySelectorAll(`[${this.pfx}]`)].concat(this.lineData);
        for (let line of this.lines) {
            line.style.visibility = 'hidden'
            this.container.appendChild(line)
        }
        const restart = this.generateRestart()

                var message = document.createElement('li')
                var content = document.createTextNode(event.data)
                message.appendChild(content)
                messages.appendChild(message)
            };
            function sendMessage(event) {
                var input = document.getElementById("messageText")
                ws.send(input.value)

                    var message = document.createElement('li')
                    var content = document.createTextNode(event.data)
                    message.appendChild(content)
                    messages.appendChild(message)
                };
                event.preventDefault()
            }
            function sendMessage(event) {
                var input = document.getElementById("messageText")