I have an image. When I left click on it, it should increase the value behind the image by 1. When I right click on it, it should decrease the value behind the image by 2.
The problem is, when I right click the image, it decreases the value correctly. However, Mozilla Firefox pops a window like "Copy this image, View this image" etc.
How can I prevent this?
That is the context menu, a standard feature of Modern OS' and not specific to Firefox.
To disable the context menu for images, use:
$(document).on('contextmenu', 'img', function() { return false; });
via DevGrow, modified to use the jQuery 1.7+ .on() to attach the event handler.