diff --git a/lib/script/script.js b/lib/script/script.js
index 6cf5853b..b4ef532f 100644
--- a/lib/script/script.js
+++ b/lib/script/script.js
@@ -2891,7 +2891,7 @@ Script.verify = function verify(input, witness, output, tx, i, value, flags) {
 Script.verifyProgram = function verifyProgram(witness, output, flags, tx, i, value) {
   let program = output.toProgram();
   let stack = witness.toStack();
-  let j, witnessScript, redeem;
+  let witnessScript, redeem;
 
   assert(program, 'verifyProgram called on non-witness-program.');
   assert((flags & Script.flags.VERIFY_WITNESS) !== 0);
@@ -2932,7 +2932,7 @@ Script.verifyProgram = function verifyProgram(witness, output, flags, tx, i, val
   }
 
   // Witnesses still have push limits.
-  for (j = 0; j < stack.length; j++) {
+  for (let j = 0; j < stack.length; j++) {
     if (stack.get(j).length > consensus.MAX_SCRIPT_PUSH)
       throw new ScriptError('PUSH_SIZE');
   }
@@ -2967,7 +2967,6 @@ Script.verifyMast = function verifyMast(program, stack, output, flags, tx, i, va
   let version = 0;
   let pathdata, depth, path, posdata, pos;
   let metadata, subscripts, ops, script;
-  let j;
 
   assert(program.version === 1);
   assert((flags & Script.flags.VERIFY_MAST) !== 0);
@@ -2989,7 +2988,7 @@ Script.verifyMast = function verifyMast(program, stack, output, flags, tx, i, va
   if (metadata[metadata.length - 1] === 0x00)
     throw new ScriptError('INVALID_MAST_STACK');
 
-  for (j = 1; j < metadata.length; j++)
+  for (let j = 1; j < metadata.length; j++)
     version |= metadata[i] << 8 * (j - 1);
 
   if (version < 0)
@@ -3020,7 +3019,7 @@ Script.verifyMast = function verifyMast(program, stack, output, flags, tx, i, va
 
   path = [];
 
-  for (j = 0; j < depth; j++)
+  for (let j = 0; j < depth; j++)
     path.push(pathdata.slice(j * 32, j * 32 + 32));
 
   posdata = stack.top(-3);
@@ -3033,7 +3032,7 @@ Script.verifyMast = function verifyMast(program, stack, output, flags, tx, i, va
     if (posdata[posdata.length - 1] === 0x00)
       throw new ScriptError('INVALID_MAST_STACK');
 
-    for (j = 0; j < posdata.length; j++)
+    for (let j = 0; j < posdata.length; j++)
       pos |= posdata[i] << 8 * j;
 
     if (pos < 0)
@@ -3047,7 +3046,7 @@ Script.verifyMast = function verifyMast(program, stack, output, flags, tx, i, va
 
   scripts.writeBytes(output.raw);
 
-  for (j = 0; j < subscripts; j++) {
+  for (let j = 0; j < subscripts; j++) {
     script = stack.top(-(4 + j));
     if (version === 0) {
       if ((scripts.written + script.length) > consensus.MAX_SCRIPT_SIZE)
@@ -3069,7 +3068,7 @@ Script.verifyMast = function verifyMast(program, stack, output, flags, tx, i, va
   if (version === 0) {
     stack.length -= 3 + subscripts;
 
-    for (j = 0; j < stack.length; j++) {
+    for (let j = 0; j < stack.length; j++) {
       if (stack.get(j).length > consensus.MAX_SCRIPT_PUSH)
         throw new ScriptError('PUSH_SIZE');
     }