If a web site places your cursor inside a search box automatically
It can be convenient to have your cursor inside a search box automatically, but it can also be very annoying, since the moment you press the down arrow at your keyboard to scroll down this page, you open instead a silly list of possible searches, and you have to move your mouse and click an empty area in the page to free your cursor.
There is nothing you can do to prevent the placing of your cursor inside a search box, if a web master decided this behavior, unless you disable all javascript functionality, which will cripple your use of the web. However, there is a way to escape the trap relatively easily.
Immediately when you realize that your cursor is in a box and you can not use your arrows to scroll the page, just press once the TAB button. This way you will immediately transfer the focus outside the search box, usually to a search button at the right. Your cursor and your keyboard arrows now are free to use them as you wish, the page can scroll.
It isn’t the ideal solution, but much faster than moving your mouse and clicking somewhere, not to mention disabling javascript.