diff --git a/op_crates/web/08_text_encoding.js b/op_crates/web/08_text_encoding.js
index 060d4879bb..f55646e12f 100644
--- a/op_crates/web/08_text_encoding.js
+++ b/op_crates/web/08_text_encoding.js
@@ -296,6 +296,19 @@
       "l9",
     ],
     "iso-8859-16": ["iso-8859-16"],
+    gbk: [
+      "chinese",
+      "csgb2312",
+      "csiso58gb231280",
+      "gb2312",
+      "gb_2312",
+      "gb_2312-80",
+      "gbk",
+      "iso-ir-58",
+      "x-gbk",
+    ],
+    gb18030: ["gb18030"],
+    big5: ["big5", "big5-hkscs", "cn-big5", "csbig5", "x-x-big5"],
     "koi8-r": ["cskoi8r", "koi", "koi8", "koi8-r", "koi8_r"],
     "koi8-u": ["koi8-ru", "koi8-u"],
     macintosh: ["csmacintosh", "mac", "macintosh", "x-mac-roman"],
@@ -348,21 +361,21 @@
   const encodingIndexes = new Map();
   // deno-fmt-ignore
   encodingIndexes.set("windows-1252", [
-    8364, 129, 8218, 402, 8222, 8230, 8224, 8225, 710, 
-    8240, 352, 8249, 338, 141, 381, 143, 144, 
-    8216, 8217, 8220, 8221, 8226, 8211, 8212, 732, 
-    8482, 353, 8250, 339, 157, 382, 376, 160, 
-    161, 162, 163, 164, 165, 166, 167, 168, 
-    169, 170, 171, 172, 173, 174, 175, 176, 
-    177, 178, 179, 180, 181, 182, 183, 184, 
+    8364, 129, 8218, 402, 8222, 8230, 8224, 8225, 710,
+    8240, 352, 8249, 338, 141, 381, 143, 144,
+    8216, 8217, 8220, 8221, 8226, 8211, 8212, 732,
+    8482, 353, 8250, 339, 157, 382, 376, 160,
+    161, 162, 163, 164, 165, 166, 167, 168,
+    169, 170, 171, 172, 173, 174, 175, 176,
+    177, 178, 179, 180, 181, 182, 183, 184,
     185, 186, 187, 188, 189, 190, 191, 192,
-    193, 194, 195, 196, 197, 198, 199, 200, 
-    201, 202, 203, 204, 205, 206, 207, 208, 
-    209, 210, 211, 212, 213, 214, 215, 216, 
-    217, 218, 219, 220, 221, 222, 223, 224, 
-    225, 226, 227, 228, 229, 230, 231, 232, 
-    233, 234, 235, 236, 237, 238, 239, 240, 
-    241, 242, 243, 244, 245, 246, 247, 248, 
+    193, 194, 195, 196, 197, 198, 199, 200,
+    201, 202, 203, 204, 205, 206, 207, 208,
+    209, 210, 211, 212, 213, 214, 215, 216,
+    217, 218, 219, 220, 221, 222, 223, 224,
+    225, 226, 227, 228, 229, 230, 231, 232,
+    233, 234, 235, 236, 237, 238, 239, 240,
+    241, 242, 243, 244, 245, 246, 247, 248,
     249, 250, 251, 252, 253, 254, 255,
   ]);