diff --git a/pdf.js b/pdf.js
index 3179f42ec..be471cfc0 100644
--- a/pdf.js
+++ b/pdf.js
@@ -816,7 +816,7 @@ var DecryptStream = (function() {
         DecodeStream.call(this);
     }
 
-    const chunkSize = 512;
+    var chunkSize = 512;
 
     constructor.prototype = Object.create(DecodeStream.prototype);
     constructor.prototype.readBlock = function() {
@@ -910,18 +910,18 @@ var Ascii85Stream = (function() {
 
 var CCITTFaxStream = (function() {
 
-    const ccittEOL = -2;
-    const twoDimPass = 0;
-    const twoDimHoriz = 1;
-    const twoDimVert0 = 2;
-    const twoDimVertR1 = 3;
-    const twoDimVertL1 = 4;
-    const twoDimVertR2 = 5;
-    const twoDimVertL2 = 6;
-    const twoDimVertR3 = 7;
-    const twoDimVertL3 = 8;
+    var ccittEOL = -2;
+    var twoDimPass = 0;
+    var twoDimHoriz = 1;
+    var twoDimVert0 = 2;
+    var twoDimVertR1 = 3;
+    var twoDimVertL1 = 4;
+    var twoDimVertR2 = 5;
+    var twoDimVertL2 = 6;
+    var twoDimVertR3 = 7;
+    var twoDimVertL3 = 8;
 
-    const twoDimTable = [
+    var twoDimTable = [
     [-1, -1], [-1, -1],               // 000000x
     [7, twoDimVertL3],                // 0000010
     [7, twoDimVertR3],                // 0000011
@@ -989,7 +989,7 @@ var CCITTFaxStream = (function() {
     [1, twoDimVert0], [1, twoDimVert0]
     ];
 
-    const whiteTable1 = [
+    var whiteTable1 = [
         [-1, -1],                 // 00000
         [12, ccittEOL],               // 00001
         [-1, -1], [-1, -1],               // 0001x
@@ -1011,7 +1011,7 @@ var CCITTFaxStream = (function() {
         [12, 2560]                    // 11111
     ];
 
-    const whiteTable2 = [
+    var whiteTable2 = [
         [-1, -1], [-1, -1], [-1, -1], [-1, -1],   // 0000000xx
         [8, 29], [8, 29],             // 00000010x
         [8, 30], [8, 30],             // 00000011x
@@ -1175,7 +1175,7 @@ var CCITTFaxStream = (function() {
         [4, 7], [4, 7], [4, 7], [4, 7]
     ];
     
-    const blackTable1 = [
+    var blackTable1 = [
         [-1, -1], [-1, -1],                   // 000000000000x
         [12, ccittEOL], [12, ccittEOL],           // 000000000001x
         [-1, -1], [-1, -1], [-1, -1], [-1, -1],       // 00000000001xx
@@ -1236,7 +1236,7 @@ var CCITTFaxStream = (function() {
         [10, 64], [10, 64], [10, 64], [10, 64]
     ];
 
-    const blackTable2 = [
+    var blackTable2 = [
         [8, 13], [8, 13], [8, 13], [8, 13],           // 00000100xxxx
         [8, 13], [8, 13], [8, 13], [8, 13],
         [8, 13], [8, 13], [8, 13], [8, 13],
@@ -1315,7 +1315,7 @@ var CCITTFaxStream = (function() {
         [7, 12], [7, 12], [7, 12], [7, 12]    
     ];
 
-    const blackTable3 = [
+    var blackTable3 = [
         [-1, -1], [-1, -1], [-1, -1], [-1, -1],       // 0000xx
         [6, 9],                       // 000100
         [6, 8],                       // 000101