Javascript variable not updating its value

Question

I set the following in my console:

document.getElementById('messsages').textContent;

which gave me the output "this is a message i sent through websocket chat!"

I then did

var convo = document.getElementById('messsages').textContent;

and typed in convo into the console and it gave me the same output as before. I then sent another message through my websocket chat and typed in convo and it gave me the old output but when I typed in document.getElementById('messsages').textContent; it gave me the new output.

Why is this? And is there a method for me to assign a variable which updates its value accordingly with my element?

No, there isn't, since everything in JS is passed by value. Instead you could use an object with getter/setter properties. — Teemu
– Teemu, Commented Feb 1, 2015 at 14:54
At this post there's a setter, a getter would be just a function returning document.getElementById('messsages').textContent in your case. — Teemu
– Teemu, Commented Feb 1, 2015 at 15:29
So basically if I paste the following in my code, then 'convo' will always equal to the current value of the div 'messsages' which contains dynamic content? : var convo = { set title(text) { document.getElementById('messsages').textContent = document.title = text; } }; — StackOverQuestions
– StackOverQuestions, Commented Feb 1, 2015 at 17:05
@StackOverQuestions Ofcourse not, you've to apply your own code to the setter structure. The linked page shows a concept of setter only, it's not a direct answer to your question. — Teemu
– Teemu, Commented Feb 1, 2015 at 19:01

guest271314 · Accepted Answer · 2015-02-01 15:28:41Z

3

Try utilizing an IIFE

var convo = function convo() {
                return (function(elem) { 
                    return elem.textContent 
                }(document.getElementById("messages"))
            };

See also MutationObserver

setInterval(function() {
 var arr = "abcdefg".split("");
 var i = 1 + Math.floor(Math.random() * arr.length -1);
 document.getElementById("messages").textContent = arr[i];
}, 2000);

var convo = function convo() {
  return (function(elem) {
    return elem.textContent
  }(document.getElementById("messages")))
};

document.addEventListener("click", function() {
  console.log(convo())
});

click
<div id="messages"></div>

edited Feb 1, 2015 at 15:28

answered Feb 1, 2015 at 15:21

guest271314

1

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2 Comments

StackOverQuestions Over a year ago

Hey it didn't work, I get the error in the console "convo is not defined".

guest271314 Over a year ago

@StackOverQuestions If possible , can post pieces tried at OP ? , create stacksnippets , jsfiddle to demonstrate ?

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