// JavaScript Document

function criaXMLHttp() {
    if (typeof XMLHttpRequest != "undefined")
        return new XMLHttpRequest();
    else if (window.ActiveXObject){
        var versoes = ["MSXML2.XMLHttp.5.0",
                       "MSXML2.XMLHttp.4.0",
                       "MSXML2.XMLHttp.3.0",
                       "MSXML2.XMLHttp",
                       "Microsoft.XMLHttp"];
        }
    for (var i = 0; i < versoes.length; i++){
        try{
            return new ActiveXObject(versoes[i]);
        }
        catch (e) {
        }
    }
    throw new Error("Seu browser nao suporta AJAX");
}

function valida(campo, valor) {
	var cont = "./ajax.php?"+campo+"="+valor;
	xmlhttp = criaXMLHttp();
	xmlhttp.open("GET",cont,true);
	xmlhttp.onreadystatechange = function(){
		if(xmlhttp.readyState == 4){
			resposta = xmlhttp.responseText;
			if(resposta == "ok"){ 
				$(".st"+campo).css({ color:"green", fontweight:"bolder", display:"none" });
				$(".st"+campo).html("&radic;");
				$(".st"+campo).fadeIn("slow");
			}
			else{
				$(".st"+campo).css({ color:"red", display:"none" });
				$(".st"+campo).html(resposta);
				$(".st"+campo).fadeIn("slow");
			}
		}
		else{
		}
	}
	xmlhttp.send(null);
}