http = getHTTPObject();
 
function getHTTPObject(){
  var xmlhttp;
 
  /*@cc_on
 
  @if (@_jscript_version >= 5)
    try {
      xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
    }catch(e){
      try{
      xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }catch(E){
      xmlhttp = false;
    }
  }
  @else
    xmlhttp = false;
  @end @*/
 
  if(!xmlhttp && typeof XMLHttpRequest != 'undefined'){
    try {
      xmlhttp = new XMLHttpRequest();
    }catch(e){
      xmlhttp = false;
    }
  }
 
  return xmlhttp;
}
 
function Buscar_Usuario(){
  var url = "email.php";
  var valores = "correo=" + document.getElementById('correo').value + "&tema=" + document.getElementById('tema').value  + "&nombre=" + document.getElementById('nombre').value + "&tipo=" + document.getElementById('tipo').value + "&tipo2=" + document.getElementById('tipo2').value + "&mensaje=" + document.getElementById('mensaje').value;
  
  http.open("POST", url, true);
  http.setRequestHeader('Content-Type','application/x-www-form-urlencoded');

  http.onreadystatechange = handleHttpResponse;
  http.send(valores); 

}
 
function handleHttpResponse(){
  if(http.readyState == 4){
    document.getElementById('a').innerHTML = '';
	document.getElementById('b').innerHTML = '';
	document.getElementById('a1').innerHTML = '';
	document.getElementById('a2').innerHTML = '';
	document.getElementById('b1').innerHTML = '';
	document.getElementById('a3').innerHTML = '';
	document.getElementById('b2').innerHTML = '';
	document.getElementById('c').innerHTML = http.responseText;
	document.getElementById('d').innerHTML = '';
	document.getElementById('e').innerHTML = '';
	document.getElementById('f').innerHTML = '';
	document.getElementById('g').innerHTML = '';
  }
}