title: Live chat using AJAX
body: <p>Hello everyone 
  I just wanted to know if I use AJAX for my chat engine, will it crash my server or it will work fine for a traffic of about 1500 people at a time ??</p>
  
  <p>Also suggest me some way to make automatic ajax request to update the contents of chat box. How much delay between consecutive query should be set so that it doesn't cause my server to overload ???</p>
  
  <p>Thanks in advance :) :)</p>