diff --git a/web/viewer.js b/web/viewer.js
index ad24bc0a7..3f6fef957 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -43,7 +43,7 @@ var ProgressBar = (function ProgressBarClosure() {
     this.height = opts.height || 1;
     this.width = opts.width || 15;
     this.units = opts.units || 'em';
-    this.percent = opts.progress || 0;
+    this.percent = opts.percent || 0;
 
     // Initialize heights
     this.progressDiv.style.height = this.height + this.units;