diff --git a/components/script/dom/eventsource.rs b/components/script/dom/eventsource.rs
index 428eabc8ad8..434a2b84504 100644
--- a/components/script/dom/eventsource.rs
+++ b/components/script/dom/eventsource.rs
@@ -183,7 +183,9 @@ impl EventSourceContext {
                 self.data.push_str(&self.value);
                 self.data.push('\n');
             },
-            "id" => mem::swap(&mut self.last_event_id, &mut self.value),
+            "id" if !self.value.contains('\0') => {
+                mem::swap(&mut self.last_event_id, &mut self.value);
+            },
             "retry" => {
                 if let Ok(time) = u64::from_str(&self.value) {
                     self.event_source
diff --git a/tests/wpt/meta/eventsource/format-field-id-null.window.js.ini b/tests/wpt/meta/eventsource/format-field-id-null.window.js.ini
deleted file mode 100644
index 30d62256c66..00000000000
--- a/tests/wpt/meta/eventsource/format-field-id-null.window.js.ini
+++ /dev/null
@@ -1,15 +0,0 @@
-[format-field-id-null.window.html]
-  [EventSource: id field set to %00%00]
-    expected: FAIL
-
-  [EventSource: id field set to x%00]
-    expected: FAIL
-
-  [EventSource: id field set to %00x]
-    expected: FAIL
-
-  [EventSource: id field set to x%00x]
-    expected: FAIL
-
-  [EventSource: id field set to %20%00]
-    expected: FAIL