diff --git a/rewriter/Cargo.lock b/rewriter/Cargo.lock
index a6c8bd3..12c2c8e 100644
--- a/rewriter/Cargo.lock
+++ b/rewriter/Cargo.lock
@@ -196,9 +196,9 @@ dependencies = [
 
 [[package]]
 name = "bytemuck"
-version = "1.18.0"
+version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "94bbb0ad554ad961ddc5da507a12a29b14e4ae5bda06b19f575a3e6079d2e2ae"
+checksum = "8334215b81e418a0a7bdb8ef0849474f40bb10c8b71f1c4ed315cff49f32494d"
 dependencies = [
  "bytemuck_derive",
 ]
@@ -1001,6 +1001,7 @@ dependencies = [
  "serde-wasm-bindgen",
  "url",
  "wasm-bindgen",
+ "web-sys",
 ]
 
 [[package]]
@@ -1011,9 +1012,9 @@ checksum = "583034fd73374156e66797ed8e5b0d5690409c9226b22d87cb7f19821c05d152"
 
 [[package]]
 name = "rustversion"
-version = "1.0.17"
+version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "955d28af4278de8121b7ebeb796b6a45735dc01436d898801014aced2773a3d6"
+checksum = "0e819f2bc632f285be6d7cd36e25940d45b2391dd6d9b939e79de557f7014248"
 
 [[package]]
 name = "ryu"
diff --git a/rewriter/Cargo.toml b/rewriter/Cargo.toml
index b8c8840..31e81ec 100644
--- a/rewriter/Cargo.toml
+++ b/rewriter/Cargo.toml
@@ -37,6 +37,7 @@ serde = "1.0.204"
 serde-wasm-bindgen = "0.6.5"
 url = "2.5.2"
 wasm-bindgen =  "0.2.92"
+web-sys = { version = "0.3.72", features = ["Url"] }
 
 [dev-dependencies]
 boa_engine = "0.19.0"
diff --git a/rewriter/build.sh b/rewriter/build.sh
index 9021eb6..b55dd7d 100755
--- a/rewriter/build.sh
+++ b/rewriter/build.sh
@@ -29,7 +29,7 @@ else
 	WASMOPTFLAGS=""
 fi
 
-time wasm-opt $WASMOPTFLAGS -O4 --vacuum --dce --enable-threads --enable-bulk-memory --enable-simd "$WASM" -o rewriter/out/optimized.wasm
+time wasm-opt $WASMOPTFLAGS -tnh -O4 --vacuum --dce --enable-threads --enable-bulk-memory --enable-simd "$WASM" -o rewriter/out/optimized.wasm
 
 mkdir dist/ || true
 
diff --git a/rewriter/src/lib.rs b/rewriter/src/lib.rs
index 73d2ab8..5d2663f 100644
--- a/rewriter/src/lib.rs
+++ b/rewriter/src/lib.rs
@@ -2,13 +2,10 @@ pub mod rewrite;
 
 use std::{panic, str::FromStr};
 
-use js_sys::{
-	global, Array, Function, Object,
-	Reflect::{self, construct},
-};
+use js_sys::{Function, Object, Reflect};
 use rewrite::{rewrite, Config, EncodeFn};
-use url::Url;
 use wasm_bindgen::{prelude::*, throw_str};
+use url::Url;
 
 #[wasm_bindgen]
 extern "C" {
@@ -40,27 +37,23 @@ fn get_obj(obj: &JsValue, k: &str) -> JsValue {
 	Reflect::get(obj, &k.into()).unwrap()
 }
 
-fn get_bool(obj: &JsValue, k: &str) -> bool {
-	Reflect::get(obj, &k.into()).unwrap().as_bool().unwrap()
-}
-
 fn get_str(obj: &JsValue, k: &str) -> String {
 	Reflect::get(obj, &k.into()).unwrap().as_string().unwrap()
 }
 
 fn get_flag(scramjet: &Object, url: &str, flag: &str) -> bool {
-	let urlconstructor = get_obj(&global(), "URL");
-	let args = Array::new();
-	args.push(&JsValue::from_str(url));
-	let url = construct(&urlconstructor.dyn_into::<Function>().unwrap(), &args).unwrap();
 	let fenabled = get_obj(scramjet, "flagEnabled")
 		.dyn_into::<Function>()
 		.unwrap();
-	return fenabled
-		.call2(&JsValue::NULL, &JsValue::from_str(flag), &url)
-		.unwrap()
+	fenabled
+		.call2(
+			&JsValue::NULL,
+			&flag.into(),
+			&web_sys::Url::new(url).expect("invalid url").into(),
+		)
+		.expect("error in flagEnabled")
 		.as_bool()
-		.unwrap();
+		.expect("not bool returned from flagEnabled")
 }
 
 fn get_config(scramjet: &Object, url: &str) -> Config {
diff --git a/rewriter/src/rewrite.rs b/rewriter/src/rewrite.rs
index ea233d3..83e14ab 100644
--- a/rewriter/src/rewrite.rs
+++ b/rewriter/src/rewrite.rs
@@ -22,7 +22,6 @@ enum JsChange {
 	},
 	SourceTag {
 		tagstart: u32,
-		tagend: usize,
 	},
 	Assignment {
 		name: String,
@@ -288,7 +287,6 @@ impl<'a> Visit<'a> for Rewriter {
 		if self.config.do_sourcemaps {
 			self.jschanges.push(JsChange::SourceTag {
 				tagstart: it.span.start,
-				tagend: it.span.end as usize,
 			});
 		}
 		walk::walk_function_body(self, it);
@@ -480,7 +478,7 @@ pub fn rewrite(js: &str, url: Url, config: Config) -> Vec<u8> {
 				rhsspan: _,
 				op: _,
 			} => entirespan.start,
-			JsChange::SourceTag { tagstart, tagend } => *tagstart,
+			JsChange::SourceTag { tagstart } => *tagstart,
 		};
 		let b = match b {
 			JsChange::GenericChange { span, text: _ } => span.start,
@@ -490,7 +488,7 @@ pub fn rewrite(js: &str, url: Url, config: Config) -> Vec<u8> {
 				rhsspan: _,
 				op: _,
 			} => entirespan.start,
-			JsChange::SourceTag { tagstart, tagend } => *tagstart,
+			JsChange::SourceTag { tagstart } => *tagstart,
 		};
 		a.cmp(&b)
 	});
@@ -519,7 +517,7 @@ pub fn rewrite(js: &str, url: Url, config: Config) -> Vec<u8> {
 	let mut sourcemap: Vec<u8> = Vec::new();
 	if ast_pass.config.do_sourcemaps {
 		sourcemap.reserve(size_estimate * 2);
-		sourcemap.extend_from_slice(&format!("{}([", ast_pass.config.pushsourcemapfn).as_bytes());
+		sourcemap.extend_from_slice(format!("{}([", ast_pass.config.pushsourcemapfn).as_bytes());
 	}
 
 	let mut offset = 0;
@@ -570,11 +568,10 @@ pub fn rewrite(js: &str, url: Url, config: Config) -> Vec<u8> {
 
 				offset = entirespan.end as usize;
 			}
-			JsChange::SourceTag { tagstart, tagend } => {
+			JsChange::SourceTag { tagstart } => {
 				let start = *tagstart as usize;
 				buffer.extend_from_slice(unsafe { js.get_unchecked(offset..start) }.as_bytes());
 
-				// let inject = format!("/*scramtag {} */", &js[start..*tagend]);
 				let inject = format!("/*scramtag {} {}*/", start, sourcetag);
 				buffer.extend_from_slice(inject.as_bytes());
 
@@ -587,7 +584,7 @@ pub fn rewrite(js: &str, url: Url, config: Config) -> Vec<u8> {
 	if ast_pass.config.do_sourcemaps {
 		sourcemap.extend_from_slice(b"],");
 		sourcemap.extend_from_slice(b"\"");
-		sourcemap.extend_from_slice(&sourcetag.as_bytes());
+		sourcemap.extend_from_slice(sourcetag.as_bytes());
 		sourcemap.extend_from_slice(b"\");\n");
 
 		sourcemap.extend_from_slice(&buffer);