function captchas_image_error (image) 
{
if (!image.timeout) return true;
image.src = image.src.replace (/^http:\/\/image\.captchas\.net/, 'http://image.backup.captchas.net');
return captchas_image_loaded (image);
}

function captchas_image_loaded (image)
{
if (!image.timeout) return true;
window.clearTimeout (image.timeout);
image.timeout = false;
return true;
}

function captchas_init(id){
var image = document.getElementById (id);
image.onerror = function() {return captchas_image_error (image);};
image.onload = function() {return captchas_image_loaded (image);};
image.timeout 
= window.setTimeout(
   "captchas_image_error (document.getElementById ('"+id+"'))",
   10000);
image.src = image.src;
}