In some browsers, some keys are shortcuts for browser actions. For example, space bar sometimes is a shortcut to scroll down the page. If any events exist for 'On key pressed' with a given key, Construct 2 blocks the browser from performing its normal action. For example, if you wish to prevent space bar scrolling down the page, add an empty 'On Space pressed' event, if you don't have one already. [/quote] From the manual entry about keyboard.
Same goes for the keyboard Up and Down keys. Be sure to "intercept" those keys in your application (as explained in the entry).
The reason you haven't noticed it earlier is that the exported index.html page is just made of the canvas and no other elements.
Also strange thread title as it is quite far from the described issue.Kyatric2012-05-14 12:34:24