1 files changed, 5 insertions, 1 deletions

diff --git a/platform/javascript/engine.js b/platform/javascript/engine.js
index 0c1337cc3..1d78f28bb 100644
--- a/platform/javascript/engine.js
+++ b/platform/javascript/engine.js
@@ -130,13 +130,17 @@
 		this.startGame = function(mainPack) {
 
 			executableName = getBaseName(mainPack);
+			var mainArgs = [];
+			if (!getPathLeaf(mainPack).endsWith('.pck')) {
+				mainArgs = ['--main-pack', getPathLeaf(mainPack)];
+			}
 			return Promise.all([
 				// Load from directory,
 				this.init(getBasePath(mainPack)),
 				// ...but write to root where the engine expects it.
 				this.preloadFile(mainPack, getPathLeaf(mainPack))
 			]).then(
-				Function.prototype.apply.bind(synchronousStart, this, [])
+				Function.prototype.apply.bind(synchronousStart, this, mainArgs)
 			);
 		};