HTML5 canvas workaround for browsers that ignore the maxWidth argument of fillText() and strokeText()

gistfile1.js

/*
	Workaround for browsers that ignore the maxWidth argument of fillText() and strokeText()
	
	Sample usage:
	    context.fillTextW("DISPROPORTIONABLENESS", 0, 10, 50);
*/
CanvasRenderingContext2D.prototype.fillTextW = function(text, x, y, maxWidth) {
	this.fillOrStrokeText("fillText", text, x, y, maxWidth);
}
CanvasRenderingContext2D.prototype.strokeTextW = function(text, x, y, maxWidth) {
	this.fillOrStrokeText("strokeText", text, x, y, maxWidth);
}
CanvasRenderingContext2D.prototype.fillOrStrokeText = function(method, text, x, y, maxWidth) {
	if (method != "fillText" && method != "strokeText") return;
	var metrics = this.measureText(text);
	if (metrics.width > maxWidth) {
		var ctx = document.createElement('canvas').getContext('2d');
		ctx.canvas.width = metrics.width;
		ctx.canvas.height = this.canvas.height;
		ctx.fillStyle = this.fillStyle;
		ctx.strokeStyle = this.strokeStyle;
		ctx.lineWidth = this.lineWidth;
		ctx.font = this.font;
		if (!this.canvas.style.direction || this.canvas.style.direction == "ltr") {
			switch (this.textAlign) {
				case "end":
				case "right": x -= maxWidth; break;
				case "center": x -= maxWidth / 2;
			}
		} else if (this.canvas.style.direction == "rtl") {
			switch (this.textAlign) {
				case "start":
				case "right": x -= maxWidth; break;
				case "center": x -= maxWidth / 2;
			}
		}
		ctx.textBaseline = this.textBaseline;
		ctx[method](text, 0, y);
		this.drawImage(ctx.canvas, x, 0, maxWidth, ctx.canvas.height);
	} else {
		this[method](text, x, y);
	}
}

Awesome--much appreciated. You left one thing out that was causing a bug in my test app though:
ctx.lineWidth = this.lineWidth;

@idwds thanks. i updated the gist.