[EmperioAf]

Все проще простого.

function array_equal ( a, b ) {
 
   if ( a.length != b.length ) return false;
    
   a.sort();
   b.sort();
    
   for ( var i in a ) {
      if ( a[i] != b[i] ) return false;
   }
   return true;
};
alert(array_equal([1,2], ['1','2']));