fix invalid character

1 files changed, 1 insertions, 1 deletions

diff --git a/src/library.js b/src/library.js
index ea44f259..2472e701 100644
--- a/src/library.js
+++ b/src/library.js
@@ -349,7 +349,7 @@ LibraryManager.library = {
                 typeof window.prompt == 'function') {
               // Browser.
               result = window.prompt('Input: ');
-              if (result === null) result = '\x00'; // cancel ==> EOF
+              if (result === null) result = String.fromCharCode(0); // cancel ==> EOF
             } else if (typeof readline == 'function') {
               // Command line.
               result = readline();