I’d recommend to use jQuery for correct cross-browser ajax requests:
function UrlExists(url, cb){
jQuery.ajax({
url: url,
dataType: 'text',
type: 'GET',
complete: function(xhr){
if(typeof cb === 'function')
cb.apply(this, [xhr.status]);
}
});
}
Usage:
UrlExists('/path/script.pl', function(status){
if(status === 200){
// file was found
}
else if(status === 404){
// 404 not found
}
});