Whatsapp web spam script

whatasppSpam.js

// for send function to select input
function dispatch(target, eventType, char) {
var evt = document.createEvent("TextEvent");    
evt.initTextEvent (eventType, true, true, window, char, 0, "en-US");
target.focus();
target.dispatchEvent(evt);
}

// enters input and clicks button
function send(msg){
a=document.getElementsByClassName('input')[1];
dispatch(a,"textInput",msg);
document.getElementsByClassName('icon-send')[0].click();
}

var myVar = setInterval(myTimer, 5000); //5 second interval

function myTimer() {
    send("Weee!");
}

It dosent work, It depends on the user on what does he type