function ajax2() {
};
ajax2.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;
}

ajax2.prototype.ocupado = function() {
        estadoAtual = this.xmlhttp.readyState;
        return (estadoAtual && (estadoAtual < 4));
}

ajax2.prototype.processa = function() {
        if (this.xmlhttp.readyState == 4 && this.xmlhttp.status == 200) {
                return true;
        }
}

ajax2.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;
}