Is there a way to listen for typing into the browser's "find" window in JavaScript?
I'd like to be able to reinterpret the search text from JavaScript. What do I need to add an event listener for?
I don't know of any way you can listen for a find-like event and if that's supported in any browser it sure isn't a portable solution.
I also don't know what you're trying to achieve but I think that your best option is to listen for the keyboard events that trigger the find window and attempt to cancel them while attempting to emulate the find-toolbar/window with JavaScript of your own. This is however a herculean (and nearly impossible) task due to some browsers customization of keyboard shortcuts depending on the localization (for instance, in IE, en-US uses Ctrl+F (for Find) while pt-PT uses Ctrl+L (for Localizar, meaning find)).
Conclusion: I think you're out of luck there...
No. There is no web standard that defines a "find" dialog, let alone events for it. The find dialog is vendor-specific and for all you know, browser X's "find" dialog lets users enter a mathematical function and match/"find" pixels on the page with it.
Hardly. Even if it were possible through some loophole to listen to the browser's built-in "find" function, it would be a privacy issue and get closed sooner or later. I'm quite sure you won't be able to listen to the keystrokes either, as they take place outside the page's focus.
来源：https://stackoverflow.com/questions/1793864/listen-for-events-from-browser-find-window-in-javascript