Though it seems no harm to the running of script, but I do want to figure out what's the cause and eliminate any potential for bugs. I've searched by google but no luck. Anyone has such experience? Thanks.
Rails will try and route any file that doesn't exist in the public/ directory. As the Bob says, something, somewhere (probably in your views) is trying to call this file.
You can tell Rails to ignore certain directories (like javascripts/ and stylesheets/) by adding the following directive to your .htaccess file:
RewriteCond %{REQUEST_URI} ^/javascripts|stylesheets|anotherdirectory/
Hope that helps,
Steve