function ajaxFunction()
  {
  
   
   
  }

  function ajax(url , call_back ) { 
		
		this.xmlHttp = null ;
		this.carga = carga ; 
		  try
			{
			// Firefox, Opera 8.0+, Safari
			this.xmlHttp=new XMLHttpRequest();
			}
		  catch (e)
			{
			// Internet Explorer
			try
			  {
			  this.xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
			  }
			catch (e)
			  {
			  try
				{
				this.xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
				}
			  catch (e)
				{
				alert("Your browser does not support AJAX!");
				return false;
				}
			  }
			}
		return this.carga( url , call_back) ;
		
		 
  }

  carga = function( url , call_back ) { 
	  
		
		this.xmlHttp.onreadystatechange=function()
		{
			if(xmlHttp.readyState==4)
			{
				call_back(xmlHttp.responseText);
			}
		}

		try
		{
			this.xmlHttp.open("GET", url ,true);
			this.xmlHttp.send(null);
		}
		catch (error)
		{
			return false 
		}
		
  }