Javascript Collision Detection System Don't Ignore Blocked Collisions

I'm having issues during a minigame development using EaselJS with my collision detection system and I need someone's help. The issue occurs when the hero (a circle bitmap) collide

Solution 1:

You have to treat horizontal and vertical collisions independently.

I've made some minor changes to your JS-fiddle: http://jsfiddle.net/Kf6cv/1/ it should work now, what I did is I split up your one check into two:

if (nextposy + height(circle) > rect.y &&
    circle.x + width(circle) > rect.x &&
    circle.x < rect.x + rect.width &&
    nextposy < rect.y + rect.height) {
    if (circle.y + height(circle) < rect.y) {
       cls("top");
    }
    if (circle.y > rect.y + rect.height) {
        cls("bottom");
    }
}

if (nextposx + width(circle) > rect.x &&
    nextposx < rect.x + rect.width &&
    circle.y + height(circle) > rect.y &&
    circle.y < rect.y + rect.height) {
    if (circle.x + width(circle) < rect.x) {
        cls("left");
    }
    if (circle.x > rect.x + rect.width) {
        cls("right");
    }
}

The reason for this is that if check both directions at once, it will prevent the movement(or make it bounce) for both directions(like the red figure in your picture) - even if it COULD move into one direction. The order of checking horizontal/vertical usually doesn't matter, it usually only matters if your "hero" approaches the other object 100% edge-to-edge. But what you could to is to first check the direction with the higher velocity, so if |velX| > |velY| then you first check for a horizontal collision.

Also I'd say it is safer to apply the new position directly after checking, right now it does two independend checks and then applies the movement of both directions - I'm not to sure about it but I could imagine that this might lead to some issues later.