Question

I have such problem: I want to show counter, which will be changing every second, so I need to change Ruby variable, which I will be using in jQuery.

EDIT: I want to make counter, that will be the same for all users.

I have counter.json.erb file:

 {
 "count": <%= @counter%>
 }

and action:

def counter
 @counter //here I need to change variable
 respond_to do |format|
 format.jsonr do
  render :json 
   end
 end
end

and I’m taking this varibale using jQuery:

$.getJSON('http://127.0.0.1:3000/counter.json', function(data) {
    alert(data.count);//alert just for testing
})

EDIT: Suggested code:

     var counter = 0
     $(document).ready(function(){
var myCounter = new flipCounter('counter', {value:counter});
$.getJSON('http://127.0.0.1:3000/counter.json', function(data) {
 myCounter.setValue(data.count);
})
});  

   setInterval(function() {
    $.getJSON('http://127.0.0.1:3000/counter.json', function(data) {
 myCounter.setValue(data.count);
   }, 1000);

and I get error:

 Uncaught SyntaxError: Unexpected end of input application.js:1

Maybe someone can suggest something ? Maybe other solution ?

Answer 1

You do not need to actually “change the variable every second”. It’s much simpler than that:

1. Pick a start time (or end time) and store the value somewhere
2. At any time, take the current time
3. Calculate the difference between the two

Done. You can repeat this algorithm at any time and always get the current status of the timer.