I'm writing a simple javascript game, which uses a 2-dimensional array as the main data structure. I wrote this function-class-thing that allows me to give any two integers, positive or negative, and this class should "wrap" those integers back on to the game grid.

For example:

var g = new Grid(10, 10);
g.set(15, -2, "hello");
g.get(5, 8); //should be "hello"

Anyway, I'm striving to improve my Javascript, so I'm wondering if there are any improvements (performance, javascriptness, etc.) that I might be able to make. Thank you!

var Grid = (function(w, h){
    this._width = w;
    this._height = h;
    this._grid = new Array((this._width * this._height) | 0);
    this.get = function(x, y){
            var coords = _normalize(x, y);
            return this._grid[(coords.y * coords.x) + coords.x];
    }
    this.set = function(x, y, item){
            var coords = _normalize(x, y);
            this._grid[(coords.y * coords.x) + coords.x] = item;
    }
    this._normalize = function(x, y){
            if(x < 0) x = (this._width + x) % this._width;
            else if(x >= this._width) x = x % this._width;
            if(y < 0) y = (this._height + y) % this._height;
            else if(y >= this._height) y = y % this._height;
            return {'x': x, 'y': y};
    }
});

Edit: some minor formatting and semicolons.

I'm writing a simple JavaScript game, which uses a 2-dimensional array as the main data structure. I wrote this function-class-thing that allows me to give any two integers, positive or negative. This class should "wrap" those integers back onto the game grid.

For example:

var g = new Grid(10, 10)
g.set(15, -2, "hello")
g.get(5, 8); //should be "hello"

Anyway, I'm striving to improve my JavaScript, so I'm wondering if there are any improvements (performance, "javascriptness", etc.) that I might be able to make.

var Grid = (function(w, h){
    this._width = w;
    this._height = h;
    this._grid = new Array((this._width * this._height) | 0);
    this.get = function(x, y){
            var coords = _normalize(x, y);
            return this._grid[(coords.y * coords.x) + coords.x];
    }
    this.set = function(x, y, item){
            var coords = _normalize(x, y);
            this._grid[(coords.y * coords.x) + coords.x] = item;
    }
    this._normalize = function(x, y){
            if(x < 0) x = (this._width + x) % this._width;
            else if(x >= this._width) x = x % this._width ;
            if(y < 0) y = (this._height + y) % this._height;
            else if(y >= this._height) y = y % this._height;
            return {'x': x, 'y': y};
    }
});