unknown scripts are running and redirecting on click to unknown websties

This seems to be a case of ISP injecting JavaScript files. Are you by any chance on the BSNL broadband?. For last few days, BSNL seems to be injecting Adware on HTTP(non encrypted) sites.

The only solution I know is to host your site on https OR change your ISP.

This issue that you are having is server-side. Likely nothing is wrong with your code, however the server is infected with malware injecting this bad code into your website.

To solve this, I would make a backup of the code you wrote, change your FTP hosting passwords, erase your server, and add your code back. If this does not solve the problem, then I would change hosting providers.