gistfile1.js

var xhr;
function requestFile( data , method , fileName , async ){
    xhr = new XMLHttpRequest(); 
    xhr.open( method , fileName , async ) ;
    
    xhr.onreadystatechange = function(){ 
      if (xhr.readyState==4){ 
        //alert("hello!")
      }
    };
    xhr.send( data ); 
}