function ajax(){
};
ajax.prototype.iniciar=function(){
	try{
        this.xmlhttp=new XMLHttpRequest();
    }catch(ee){
    	try{
            this.xmlhttp=new ActiveXObject("Msxml2.XMLHTTP");
        }
		catch(e){
            try{
                this.xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
            }
			catch(E){
                this.xmlhttp=false;
            }
        }
    }
    return true;
}

ajax.prototype.ocupado=function(){
    estadoAtual=this.xmlhttp.readyState;
    return(estadoAtual && (estadoAtual<4));
}

ajax.prototype.processa=function(){
    if(this.xmlhttp.readyState==4 && this.xmlhttp.status==200){
        return true;
    }
}

ajax.prototype.enviar=function(url, metodo, modo){
	if(!this.xmlhttp){
        this.iniciar();
    }
    if(!this.ocupado()){
        if(metodo=="GET"){
            this.xmlhttp.open("GET", url, modo);
            this.xmlhttp.send(null);
        }
		else{        
            this.xmlhttp.open("POST", url, modo);
            this.xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
            this.xmlhttp.setRequestHeader("Cache-Control", "no-store, no-cache, must-revalidate");
            this.xmlhttp.setRequestHeader("Cache-Control", "post-check=0, pre-check=0");
            this.xmlhttp.setRequestHeader("Pragma", "no-cache");
            this.xmlhttp.send(url);
        }    
        if (this.processa){
			return unescape(this.xmlhttp.responseText.replace(/\+/g," "));
        }
    }
    return false;
}