Hoe do I get the request.var value to controller?

I’m trying to use a function in js(though not completely familiar with js) to get a value from js to controller. Currently my reply comes as a blank message. How can I get it done with this code? Controller: reply = request.vars

// install user input textfield   this.typeInput = function(callbackFn) {     var inputWrap = document.createElement("div id='myMessage'")     inputWrap.className = "input-wrap"     var inputText = document.createElement("textarea")     inputText.setAttribute("placeholder", "Ask me anything...")     inputWrap.appendChild(inputText)     var input = document.getElementById("myMessage");     alert(input);     inputText.addEventListener("keypress", function(e) {       // register user input       if (e.keyCode == 13) {         e.preventDefault()         typeof bubbleQueue !== false ? clearTimeout(bubbleQueue) : false // allow user to interrupt the bot         var lastBubble = document.querySelectorAll(".bubble.say")         lastBubble = lastBubble[lastBubble.length - 1]         lastBubble.classList.contains("reply") &&         !lastBubble.classList.contains("reply-freeform")           ? lastBubble.classList.add("bubble-hidden")           : false         addBubble(           '<span class="bubble-button bubble-pick">' + this.value + "</span>",           function() {},           "reply reply-freeform"         )         // callback         typeof callbackFn === "function"           ? callbackFn({               input: this.value,               convo: _convo,               standingAnswer: standingAnswer             })           : false         this.value = ""       }     })     container.appendChild(inputWrap)     bubbleWrap.style.paddingBottom = "100px"     inputText.focus()   }   inputCallbackFn ? this.typeInput(inputCallbackFn) : false