1 files changed, 31 insertions, 16 deletions

diff --git a/lib/js/urweb.js b/lib/js/urweb.js
index 0182440e..0b482b07 100644
--- a/lib/js/urweb.js
+++ b/lib/js/urweb.js
@@ -229,11 +229,15 @@ var isLowerBitm = [
 	];
 
 function isLower(c) {
-	var cp = ord(c);
-	var idx = Math.floor(cp / 32);
-	var byt = isLowerBitm[idx];
+    var cp = ord(c);
+    var idx = Math.floor(cp / 32);
+    var byt = isLowerBitm[idx];
+    if (byt)
+    {
 	var mask = Math.pow(2, cp - idx * 32);
 	return (byt & mask) != 0;
+    }
+    return false;
 }
 
 var isUpperBitm = [
@@ -440,11 +444,14 @@ var isUpperBitm = [
 	];
 
 function isUpper(c) {
-	var cp = ord(c);
-	var idx = Math.floor(cp / 32);
-	var byt = isUpperBitm[idx];
+    var cp = ord(c);
+    var idx = Math.floor(cp / 32);
+    var byt = isUpperBitm[idx];
+    if (byt) {
 	var mask = Math.pow(2, cp - idx * 32);
 	return (byt & mask) != 0;
+    }
+    return false;
 }
 
 var isAlphaBitm = [
@@ -756,11 +763,14 @@ var isAlphaBitm = [
 	];
 
 function isAlpha(c) {
-	var cp = ord(c);
-	var idx = Math.floor(cp / 32);
-	var byt = isAlphaBitm[idx];
+    var cp = ord(c);
+    var idx = Math.floor(cp / 32);
+    var byt = isAlphaBitm[idx];
+    if (byt) {
 	var mask = Math.pow(2, cp - idx * 32);
 	return (byt & mask) != 0;
+    }
+    return false;
 }
 
 var isDigitBitm = [
@@ -963,11 +973,14 @@ var isDigitBitm = [
 	];
 
 function isDigit(c) {
-	var cp = ord(c);
-	var idx = Math.floor(cp / 32);
-	var byt = isDigitBitm[idx];
+    var cp = ord(c);
+    var idx = Math.floor(cp / 32);
+    var byt = isDigitBitm[idx];
+    if (byt) {
 	var mask = Math.pow(2, cp - idx * 32);
 	return (byt & mask) != 0;
+    }
+    return false;
 }
 
 function isAlnum(c) { return isAlpha(c) || isDigit(c); }
@@ -1316,14 +1329,16 @@ var isPrintBitm = [
 	];
 
 function isPrint(c) {
-	var cp = ord(c);
-	var idx = Math.floor(cp / 32);
-	var byt = isPrintBitm[idx];
+    var cp = ord(c);
+    var idx = Math.floor(cp / 32);
+    var byt = isPrintBitm[idx];
+    if (byt) {
 	var mask = Math.pow(2, cp - idx * 32);
 	return (byt & mask) != 0;
+    }
+    return false;
 }
 
-
 function toLower(c) {
     var cp = ord(c);