// ------------------------

function cadastra(formId,canvasId,file) {
  if (!document.getElementById) return false;
  if (!document.getElementById(formId)) return false;
  document.getElementById(formId).onsubmit = function() {
    var data = "";
    for (var i=0; i<this.elements.length; i++) {
	  if(this.elements[i].value == ""){
		  alert("Todos os campos devem ser preenchidos.");
		  return false
	  }
      data+= this.elements[i].name;
      data+= "=";
      data+= escape(this.elements[i].value);
      data+= "&";
    }
	return (!sendData(data,file,canvasId));
  };
}

function sendData(data,file,canvasId) {
  var canvas = document.getElementById(canvasId);
  canvas.innerHTML = "Carregando...";
  var request = getHTTPObject();
  if (request) {
    request.onreadystatechange = function() {
      parseResponse(request,canvasId);
    };
    request.open( "POST", file, true );
    request.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
    request.send(data);
    return true;
  } else {
    return false;
  }
}

function parseResponse(request,canvasId) {
  if (request.readyState == 4) {
    if (request.status == 200) {
		var canvas = document.getElementById(canvasId);
		canvas.innerHTML = request.responseText;
    }
  }
}

function getElementsByClassName(name) {
  var results = new Array();
  var elems = document.getElementsByTagName("*");
  for (var i=0; i<elems.length; i++) {
    if (elems[i].className.indexOf(name) != -1) {
      results[results.length] = elems[i];
    }
  }
  return results;
}

function getHTTPObject() {
  var xhr = false;
  if (window.ActiveXObject) {
    try {
      xhr = new ActiveXObject("Msxml2.XMLHTTP");
    } catch(e) {
      try {
        xhr = new ActiveXObject("Microsoft.XMLHTTP");
      } catch(e) {
        xhr = false;
      }
    }
  } else if (window.XMLHttpRequest) {
    try {
      xhr = new XMLHttpRequest();
    } catch(e) {
      xhr = false;
    }
  }
  return xhr;
}