The main applications of JS:
- Creating HTML tags, delete, modify existing, etc;
- Reaction to the manipulation, processing mouse clicks, cursor movement and actions with the keyboard;
- Sending requests to servers and receiving information without page refresh;
- Getting and setting cookie, the request information message output;
- Many of the actions of JS is limited to one work window and a page.
Consider what can not be done with the use of scripts:
- JS has no direct access to the operating system, so can't read and make copies of the files on your hard disk;
- JS does not interact with more than one tab. Derogation from the rules are the tabs that were opened by the program (identical to the Protocol or domain).