Final answer:
The same-origin policy is the reason why accessing scripts from one domain to another is not permitted.
Step-by-step explanation:
Most of the time, accessing scripts from one domain to another- for instance- from to - isn't permitted because the same-origin policy allows scripts to run only if they match in protocol (http vs https, for example), hostname( vs ) and port (port 80 or 443 for http or https traffic by default). For obvious reasons, browsers enforce these rules to block potentially malicious exploits. It would be a poor sort of internet on which clicking any link opened up threats from other sites.