How can I use JavaScript on the client side to detect if the page was encrypted?

Use window.location.protocol to check if it is https:

function isSecure(){   return window.location.protocol == 'https:';}

Alternatively you can omit specifying "window" if you don't have a locally scoped location.

function isSecure(){   return location.protocol == 'https:';}

javascript http https

As google analytics taught me:

if ("https:" == document.location.protocol) {    /* secure */} else {    /* unsecure */}

javascript http https

Second method for newest browsers:

var secure = window.isSecureContext;

or just get isSecureContext:

if (isSecureContext) {   ...}

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