function createXMLHttpRequest() { 
  
var ua; 
  
if(window.XMLHttpRequest) { 
try { 
ua = new XMLHttpRequest(); 
} catch(e) { 
ua = false; 
} 
} else if(window.ActiveXObject) { 
try { 
ua = new ActiveXObject("Microsoft.XMLHTTP"); 
} catch(e) { 
ua = false; 
} 
} 
return ua; 
}