title: What happen if I use setInterval to call ajax every 3 second or less?
body: <p>I have a very short question. What happen if I use setInterval method to call an ajax function like checking message in inbox every 3 second (or if I can do in every 1 second would be nice!)</p>
  
  <p>Well this is what I use:</p>
  
  <pre><code>setInterval(function() {
  chk_inbx (var1, var2);
  
  }, 8000);
  </code></pre>
  
  <p>I call this function every 8 second right now. I see no problem. (or maybe I don´t have so many users right now)</p>
  
  <p>But what happen if I change it from 8000 to 3000 or even 1000 ?</p>
  
  <p><strong>UPDATE</strong>
  I have test the polling (<a href="https://stackoverflow.com/questions/15588344/long-polling-in-php-starts-hanging-after-5-requests-to-database">LONG POLLING (in php) starts hanging after 5 requests to database</a>
  )</p>
  
  <p>I wonder what ´s diferences between setTimeout and setTimeout with polling.
  What I understand is in php file they put the sleep(); function and use timestamp
  to determin if the data is old or not.</p>
  
  <p>But mine, I use N nd Y to determine if msg is read or not. if N then show the rowCount.</p>
  
  <p>So what is the different ? can anyone help me ?</p>