[i.o.]

 
var a:Array = ['a','b','c','d'];
var b:Array = ['b','d'];
 
var c:Array = getSubtraction( a, b );
 
 
trace( c );
 
 
 
function getSubtraction( arrA:Array, arrB:Array ):Array
{
	var arrOut:Array = [];
 
	var _isFound:Boolean;
 
	var i:int;
	var j:int;
 
	var li:int = arrA.length;
	var lj:int = arrB.length;
 
	for( i=0; i < li; i+=1 )
	{
		_isFound = false;
 
		for( j=0; j < lj; j+=1 )
		{
			if( arrA[i] === arrB[j] )
			{
				_isFound = true;
				break;
			}
		}
 
		if( !_isFound )
		{
			arrOut.push( arrA[i] );
		}
	}
 
	return arrOut;
}