Tile-based collision detection

[Murtada-King]

Hello guys,

I've been working on a little game project of mine where I have a tile-based engine.
I've got a lot so far... But the collision detection is not working for me.
As far as I can see, it should work, but it just doesn't somehow.

I've got a demo here:
http://murtada.nl/experiments/tiles/

Move with WASD keys.

The edge function for collidable tiles:

function get_edges(object):Array
{
	var r = Math.floor(Math.round(object.x+object.speedX+object.width*0.5)/WORLD.tileWidth);
	var l = Math.floor(Math.round(object.x+object.speedX-object.width*0.5)/WORLD.tileWidth);
	var b = Math.floor(Math.round(object.y+object.speedY+object.height*0.5)/WORLD.tileHeight);
	var t = Math.floor(Math.round(object.y+object.speedY-object.height*0.5)/WORLD.tileHeight);
	
	var tr = currentLevel[t][r];
	var tl = currentLevel[t][l];
	var bl = currentLevel[b][l];
	var br = currentLevel[b][r];
	
	var finalArray:Array = new Array();
	finalArray["tr"] = tr;
	finalArray["br"] = br;
	finalArray["bl"] = bl;
	finalArray["tl"] = tl;
	finalArray["b"] = b;
	finalArray["t"] = t;
	finalArray["l"] = l;
	finalArray["r"] = r;
	return finalArray;
}

and here's the code for the actual collision detection and collision resolving:

function CollisionObjectTile(object)
{
	var edges:Array = get_edges(object);

	// GOING DOWN
	if (object.speedY > 0)
	{
		if (in_array(edges["br"],collidables) || in_array(edges["bl"],collidables))
		{
			object.speedY = 0;
			object.y = edges["b"] * WORLD.tileHeight - object.height * 0.5;
			object.onGround = true;

			if (! object.walking)
			{
				object.speedX *=  WORLD.groundFriction;
			}
		}
	}
	// GOING UP
	else if (object.speedY < 0)
	{
		if (in_array(edges["tr"],collidables) || in_array(edges["tl"],collidables))
		{
			object.speedY = 0;
			object.y = (edges["t"]+1) * WORLD.tileHeight + object.height * 0.5;
			if (! object.walking)
			{
				object.speedX *=  WORLD.groundFriction;
			}
		}
	}

	edges = get_edges(object);
	// GOING LEFT
	if (object.speedX < 0)
	{
		if (in_array(edges["tl"],collidables) || in_array(edges["bl"],collidables))
		{
			object.x = (edges["l"]+1) * WORLD.tileWidth + object.width * 0.5;
			object.speedX = 0;
		}

		
	}
	// GOING RIGHT
	else if (object.speedX > 0)
	{
		if (in_array(edges["tr"],collidables) || in_array(edges["br"],collidables))
		{
			object.x = edges["r"] * WORLD.tileWidth - object.width * 0.5;
			object.speedX = 0;

		}
	}
}

I'd greatly appreciate it if someone could point me in the right direction or figure out what exactly I am doing wrong.

Thanks!