diff --git a/src/core/cmap.js b/src/core/cmap.js
index f6b6e8679..3f992bfb7 100644
--- a/src/core/cmap.js
+++ b/src/core/cmap.js
@@ -588,7 +588,7 @@ var BinaryCMapReader = (function BinaryCMapReaderClosure() {
             stream.readHex(start, dataSize);
             stream.readHexNumber(end, dataSize);
             addHex(end, start, dataSize);
-            code = stream.readNumber();
+            stream.readNumber(); // code
             // undefined range, skipping
             for (i = 1; i < subitemsCount; i++) {
               incHex(end, dataSize);
@@ -596,7 +596,7 @@ var BinaryCMapReader = (function BinaryCMapReaderClosure() {
               addHex(start, end, dataSize);
               stream.readHexNumber(end, dataSize);
               addHex(end, start, dataSize);
-              code = stream.readNumber();
+              stream.readNumber(); // code
               // nop
             }
             break;
diff --git a/src/core/crypto.js b/src/core/crypto.js
index e87c3e10e..4913ef421 100644
--- a/src/core/crypto.js
+++ b/src/core/crypto.js
@@ -860,7 +860,7 @@ var AES128Cipher = (function AES128CipherClosure() {
   }
 
   function encrypt128(input, key) {
-    var t, u, v, k;
+    var t, u, v, j, k;
     var state = new Uint8Array(16);
     state.set(input);
     for (j = 0; j < 16; ++j) {
@@ -893,7 +893,7 @@ var AES128Cipher = (function AES128CipherClosure() {
       state[11] = u;
       state[15] = t;
       // MixColumns
-      for (var j = 0; j < 16; j += 4) {
+      for (j = 0; j < 16; j += 4) {
         var s0 = state[j + 0], s1 = state[j + 1];
         var s2 = state[j + 2], s3 = state[j + 3];
         t = s0 ^ s1 ^ s2 ^ s3;
@@ -1169,6 +1169,7 @@ var AES256Cipher = (function AES256CipherClosure() {
 
     result.set(cipherKey);
     for (var j = 32, i = 1; j < b; ++i) {
+      var t1, t2, t3, t4;
       if (j % 32 === 16) {
         t1 = s[t1];
         t2 = s[t2];
@@ -1176,8 +1177,10 @@ var AES256Cipher = (function AES256CipherClosure() {
         t4 = s[t4];
       } else if (j % 32 === 0) {
         // RotWord
-        var t1 = result[j - 3], t2 = result[j - 2],
-          t3 = result[j - 1], t4 = result[j - 4];
+        t1 = result[j - 3];
+        t2 = result[j - 2];
+        t3 = result[j - 1];
+        t4 = result[j - 4];
         // SubWord
         t1 = s[t1];
         t2 = s[t2];
@@ -1282,7 +1285,7 @@ var AES256Cipher = (function AES256CipherClosure() {
   }
 
   function encrypt256(input, key) {
-    var t, u, v, k;
+    var t, u, v, i, j, k;
     var state = new Uint8Array(16);
     state.set(input);
     for (j = 0; j < 16; ++j) {
@@ -1315,7 +1318,7 @@ var AES256Cipher = (function AES256CipherClosure() {
       state[11] = u;
       state[15] = t;
       // MixColumns
-      for (var j = 0; j < 16; j += 4) {
+      for (j = 0; j < 16; j += 4) {
         var s0 = state[j + 0], s1 = state[j + 1];
         var s2 = state[j + 2], s3 = state[j + 3];
         t = s0 ^ s1 ^ s2 ^ s3;
diff --git a/src/core/fonts.js b/src/core/fonts.js
index 4d7354648..475be25a3 100644
--- a/src/core/fonts.js
+++ b/src/core/fonts.js
@@ -2447,7 +2447,6 @@ var Font = (function FontClosure() {
               }
               if (glyphId > 0 && hasGlyph(glyphId)) {
                 charCodeToGlyphId[charCode] = glyphId;
-                found = true;
               }
             }
           }
@@ -3084,7 +3083,6 @@ var Type1Font = (function Type1FontClosure() {
 
     // Get the data block containing glyphs and subrs information
     var headerBlock = getHeaderBlock(file, headerBlockLength);
-    headerBlockLength = headerBlock.length;
     var headerBlockParser = new Type1Parser(headerBlock.stream, false,
                                             SEAC_ANALYSIS_ENABLED);
     headerBlockParser.extractFontHeader(properties);
@@ -3097,7 +3095,6 @@ var Type1Font = (function Type1FontClosure() {
 
     // Decrypt the data blocks and retrieve it's content
     var eexecBlock = getEexecBlock(file, eexecBlockLength);
-    eexecBlockLength = eexecBlock.length;
     var eexecBlockParser = new Type1Parser(eexecBlock.stream, true,
                                            SEAC_ANALYSIS_ENABLED);
     var data = eexecBlockParser.extractFontProgram();
diff --git a/src/core/parser.js b/src/core/parser.js
index 074990e78..54cfc3568 100644
--- a/src/core/parser.js
+++ b/src/core/parser.js
@@ -563,7 +563,7 @@ var Parser = (function ParserClosure() {
       // when we can be absolutely certain that it actually is empty.
       if (maybeLength === 0) {
         warn('Empty "' + name + '" stream.');
-        return new NullStream(stream);
+        return new NullStream();
       }
       try {
         var xrefStreamStats = this.xref.stats.streamTypes;
@@ -623,7 +623,7 @@ var Parser = (function ParserClosure() {
           throw ex;
         }
         warn('Invalid stream: \"' + ex + '\"');
-        return new NullStream(stream);
+        return new NullStream();
       }
     },
   };
diff --git a/src/core/type1_parser.js b/src/core/type1_parser.js
index a0513efcf..2bbf259c2 100644
--- a/src/core/type1_parser.js
+++ b/src/core/type1_parser.js
@@ -578,7 +578,7 @@ var Type1Parser = (function Type1ParserClosure() {
           case 'Subrs':
             this.readInt(); // num
             this.getToken(); // read in 'array'
-            while ((token = this.getToken()) === 'dup') {
+            while (this.getToken() === 'dup') {
               var index = this.readInt();
               length = this.readInt();
               this.getToken(); // read in 'RD' or '-|'