You will need at least 2 blocks.
1 block is a wall,
the other block is a player.

You have the player, now you just need a block.
I use this function to determine whether 2 blocks have collided:

function checkCollision(rect1, rect2)
{
    if (rect1.x < rect2.x + rect2.width &&
        rect1.x + rect1.width > rect2.x &&
        rect1.y < rect2.y + rect2.height &&
        rect1.y + rect1.height > rect2.y)
    {
        return true;
    }

    return false;
}

and call it with

if (checkCollision(player_block, wall_block))
{
    // Player is colliding with the block
}

Well, right now you will not be able to easily make a block because of how your level is set up.
Try this tutorial.