function loginExist(obj){
	var ajax=criaAJAX();
	if (obj.value!=''){
		ajax.open("POST","/global/ajax/loginExist.asp",true);
		ajax.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
		ajax.setRequestHeader("Content-Length", 1);
		ajax.onreadystatechange=function (){
			if(ajax.readyState==4){
				switch (ajax.responseText){
				case "1":alert('Login já existe');obj.value='';obj.focus();return 1;
				case "0":return 0;
				}
			}
		}
		ajax.send("usuario="+obj.value);
	}
}