www: Correct UX of the copy button

[BeniCheni]

Fixes #2397.

Triaged. It seems that the click on the copy button would run into a console error about CSP (Content Security Policy) Unsafe_inline_script:

Refused to execute inline event handler because it violates the following Content Security Policy directive: "script-src 'self'". Either the 'unsafe-inline' keyword, a hash ('sha256-...'), or a nonce ('nonce-...') is required to enable inline execution.

Attempt to fix by a JavaScript solution

[pietroalbini]

Our CSP is defined in www/website_config.json, so eventual changes should be done there.

I'd prefer not to tweak the CSP: we intentionally made it as strict as possible, and this PR allows way more stuff than necessary (including unsafe-inline which kinda defeats the point of the CSP). If the goal is fixing the copy button not working, the better solution would be to move the onclick to rustup.js:

var buttons = document.querySelectorAll(".copy-button");
for (int i = 0; i < buttons.length; i++) {
    buttons[i].addEventListener("click", handle_copy_button_click);
}

[BeniCheni]

the better solution would be to move the onclick to rustup.js

I've tried out @pietroalbini's suggestion, and tested locally using "test" keyword to validate the style & functionality of the copy button.

platform-instructions-unix

platform-instructions-win32

platform-instructions-win64

platform-instructions-unknown

platform-instructions-default

[kinnison]

So, I personally have no reason to believe this won't work, providing @BeniCheni has checked it on both chrome and firefox, and via an HTTP service with a similar CSP to the one on rustup.rs. @pietroalbini do you think this is OK?

[pietroalbini]

Yeah this looks correct.