diff --git a/index.html b/index.html
index fced9ad..85cb3c0 100644
--- a/index.html
+++ b/index.html
@@ -274,7 +274,7 @@
 
 			function parse() {
 				var type = dataView.getUint8(offset);
-				var value, length;
+				var value, length, ms32b, ls32b;
 				switch (type) {
 					// nil
 				case 0xc0:
@@ -347,10 +347,12 @@
 					return value;
 					// uint64
 				case 0xcf:
-					// value = buffer.readUInt64BE(offset + 1);
-					log(offset, 9, "uint64 marker - cannot parse uint64 to javascript, setting to Infinity");
+					ms32b = dataView.getUint32(offset + 1);
+					ls32b = dataView.getUint32(offset + 5);
+					value = (BigInt(ms32b) << 32n) + BigInt(ls32b);
+					log(offset, 9, "uint64 value " + value);
 					offset += 9;
-					return Infinity;
+					return value;
 					// int 8
 				case 0xd0:
 					value = dataView.getInt8(offset + 1);
@@ -371,9 +373,12 @@
 					return value;
 					// int 64
 				case 0xd3:
-					log(offset, 9, "int64 marker - cannot parse uint64 to javascript, setting to Infinity");
+					ms32b = dataView.getUint32(offset + 1);
+					ls32b = dataView.getUint32(offset + 5);
+					value = BigInt.asIntN(64, (BigInt(ms32b) << 32n) + BigInt(ls32b));
+					log(offset, 9, "int64 value " + value);
 					offset += 9;
-					return Infinity;
+					return value;
 					// map 16
 				case 0xde:
 					length = dataView.getUint16(offset + 1);
@@ -534,7 +539,7 @@
 					var byteVal = dataView.getUint8(i);
 					displayByte(byteVal, i);
 				}
-				jsonobj.innerHTML = JSON.stringify(decode(dataView), null, 2);
+				jsonobj.innerHTML = JSON.stringify(decode(dataView), bigIntJSONReplacer, 2);
 				indent();
 			} catch (e) {
 				errlog("Error parsing input: " + e.message);
@@ -542,6 +547,12 @@
 			}
 		}
 
+		function bigIntJSONReplacer(key, value) {
+			return typeof value === 'bigint'
+				? value.toString()
+				: value;
+		}
+
 		function getQSParams() {
 			return window.location.search
 				.substr(1)