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;

};

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']));

a.sort();
b.sort();

function array_equal ( a, b ) {
  return  a.join('\n&\n') == b.join('\n&\n') ;
}

function array_equal ( a, b ) {
  return  a.join('\n&\n') == b.join('\n&\n') ;
}
var a;
alert([array_equal ( [a], [] ),[a].length,[].length]);
alert(array_equal ( ['1'], [[1]] ));

var a = [1,2,3];
var b = [1,2,3];
var c = [[1,2,3]];

alert(JSON.stringify(a) == JSON.stringify(b));
alert(JSON.stringify(a) == JSON.stringify(c));

alert(JSON.stringify([Array]) === JSON.stringify([null]));

var a = [1,2,3];
var b = [1,2,3];
var c = [];
var d = [Array];
var e =[null];
function array_equal ( a, b ) {
    return a.every(function(el, i){
        return el === b[i];
    }, b);
}

alert(array_equal ( a, b ));
alert(array_equal ( a, c ));
alert(array_equal ( d, e ));