By default browsers let us select the text in the browser using the keyboard, pressing the cmd-A combination on a Mac for example, or using the mouse.
How can you disable that, to make your web page behave more like an app and less like a document?
user-select: none; CSS rule.
You need to use browser prefixes, as https://caniuse.com/#feat=user-select-none tells us:
-webkit-touch-callout: none; -webkit-user-select: none; -khtml-user-select: none; -moz-user-select: none; -ms-user-select: none; user-select: none;
One thing I use sometimes is to make all the app interface unselectable applying
user-select: none; on the body element, then I can re-enable it on specific elements, using: