Support Firefox 3.6 still, with surprising little effort.

Why, I don't really know :)

build/build.sh

@@ -32,7 +32,7 @@ fi
 
 ./preprocess.sh $MODE ../src/paper.js "-i '../src/constants.js'" ../dist/paper-full.js
 ./preprocess.sh $MODE ../src/paper.js "-o '{ \"paperScript\": false, \"palette\": false }' -i '../src/constants.js'" ../dist/paper-core.js
-./preprocess.sh $MODE ../src/paper.js "-o '{ \"environment\": \"node\" }' -i '../src/constants.js'" ../dist/paper-node.js 
+./preprocess.sh $MODE ../src/paper.js "-o '{ \"environment\": \"node\", \"legacy\": false }' -i '../src/constants.js'" ../dist/paper-node.js 
 
 # Remove the existing file and copy paper-full.js to paper.js now
 if [ -f ../dist/paper.js ]

src/canvas/BlendMode.js

@@ -232,20 +232,24 @@ var BlendMode = new function() {
 	Base.each(modes, function(func, mode) {
 		// Blend #330000 (51) and #aa0000 (170):
 		// Multiplying should lead to #220000 (34)
-		ctx.save();
 		// For darken we need to reverse color parameters in order to test mode.
 		var darken = mode === 'darken',
 			ok = false;
-		ctx.fillStyle = darken ? '#300' : '#a00';
+		ctx.save();
-		ctx.fillRect(0, 0, 1, 1);
+		// FF 3.6 throws exception when setting globalCompositeOperation to
-		ctx.globalCompositeOperation = mode;
+		// unsupported values.
-		if (ctx.globalCompositeOperation === mode) {
+		try {
-			ctx.fillStyle = darken ? '#a00' : '#300';
+			ctx.fillStyle = darken ? '#300' : '#a00';
 			ctx.fillRect(0, 0, 1, 1);
-			ok = ctx.getImageData(0, 0, 1, 1).data[0] !== (darken ? 170 : 51);
+			ctx.globalCompositeOperation = mode;
-		}
+			if (ctx.globalCompositeOperation === mode) {
-		nativeModes[mode] = ok; 
+				ctx.fillStyle = darken ? '#a00' : '#300';
+				ctx.fillRect(0, 0, 1, 1);
+				ok = ctx.getImageData(0, 0, 1, 1).data[0] !== darken ? 170 : 51;
+			}
+		} catch (e) {}
 		ctx.restore();
+		nativeModes[mode] = ok; 
 	});
 	CanvasProvider.release(ctx);
 

src/legacy.js

@@ -0,0 +1,23 @@
+/*
+ * Paper.js - The Swiss Army Knife of Vector Graphics Scripting.
+ * http://paperjs.org/
+ *
+ * Copyright (c) 2011 - 2014, Juerg Lehni & Jonathan Puckey
+ * http://scratchdisk.com/ & http://jonathanpuckey.com/
+ *
+ * Distributed under the MIT license. See LICENSE file for details.
+ *
+ * All rights reserved.
+ */
+
+// Support for legacy browsers (mainly FF 3.6). Remove 2nd half of 2014?
+
+if (!Array.isArray) {
+	Array.isArray = function(obj) {
+		return Object.prototype.toString.call(obj) === '[object Array]';
+	};
+}
+
+if (!document.head) {
+	document.head = document.getElementsByTagName('head')[0];
+}

src/options.js

@@ -18,6 +18,7 @@ var __options = {
 	parser: 'acorn',
 	version: 'dev',
 	environment: 'browser',
+	legacy: true,
 	stats: true,
 	svg: true,
 	fatlineClipping: true,

src/paper.js

@@ -40,6 +40,10 @@ var paper = new function(undefined) {
 /*#*/ include('../bower_components/stats.js/build/stats.min.js');
 /*#*/ } // __options.stats
 
+/*#*/ if (__options.legacy) {
+	/*#*/ include('legacy.js');
+/*#*/ } // __options.legacy
+
 /*#*/ if (__options.version == 'dev') {
 /*#*/ include('constants.js');
 /*#*/ } // __options.version == 'dev'