JavaScript arrays are lolsome :)

gistfile1.md

Two correct ways to use for/in in JavaScript:

for (var i in a) {
  if (!a.hasOwnProperty(i)) continue; 
  
  // loop body
}

for (var i in a) {  
  if (String(Math.floor(Math.abs(Number(i))))) !== i) continue; // ROFL !?
  
  // loop body
}

The first way is not actually bullet-proof (e.g. when you have an array a and somewhere in your code there's a['foo'] = 'bar', for example).