Using alert() for debugging can get tiresome. Dojo has a built in logging mechanism. It's pretty easy to use.
First, enable debugging. This is done by setting the isDebug property of Dojo configuration to true. Next, replace the alert() function with console.debug().
function showEvent(theEvent) {
console.debug("Event: " + theEvent.type +
" for element: " + theEvent.target.nodeName);
}

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