  Ajax    "Ajax  ". 
 ,       HTML, CSS,
Javascript, DHTML, PHP  . 
          -
 . 
        Web-,   Ajax.
    Ajax: JavaScript, CSS, DOM  
XMLHttpRequest. 
 ,       , 
     "--" 
   ,       
 -  ,   
  . 
      Ajax.
      
,   JavaScript  . 
           
 . 
    ajax,    .