Si no te es muy drástico cambia el $.post por $.ajax y para enviar archivos el parametro processData:false siempre debe estar en false
Código Javascript
:
Ver original$.ajax({
url: "ajax_php_file.php", // Url to which the request is send
type: "POST", // Type of request to be send, called as method
data: new FormData(this), // Data sent to server, a set of key/value pairs (i.e. form fields and values)
contentType: false, // The content type used when sending data to the server.
cache: false, // To unable request pages to be cached
processData:false, // To send DOMDocument or non processed data file it is set to false
success: function(data) // A function to be called if request succeeds
{
$('#loading').hide();
$("#message").html(data);
}
});