使用ajax加载的Javascript只在第一次运行

I've created two simple testpages. One loads the other one using XMLHttpRequest. (just a page using slimbox to display a image) This works perfect the first time. But when trying to run it again, by pressing the button again, it does not work anymore. When I reload the whole page, it works the first time again. Do I have to un-load or re-load the scripts or something? I know It is double of the script-tags here, don't know why but its the only way I got it to work in the first place. How come it only works the first time? I've created two simple testpages. One loads th