Simple script for checking if the browser has flash enabled. Most often used for swapping a slide show element.

flashChecker.js

var hasFlash = false;
try {
  var fo = new ActiveXObject('ShockwaveFlash.ShockwaveFlash');
  if(fo) hasFlash = true;
}catch(e){
  if(navigator.mimeTypes ["application/x-shockwave-flash"] != undefined) hasFlash = true;
}