diff --git a/cwriter/util_wasm.go b/cwriter/util_wasm.go
new file mode 100644
index 00000000..7efaa619
--- /dev/null
+++ b/cwriter/util_wasm.go
@@ -0,0 +1,6 @@
+//+build wasm js
+
+package cwriter
+
+// There is no ioctl on wasm, so we just use a dummy value.
+const ioctlReadTermios = 0
diff --git a/cwriter/writer_posix.go b/cwriter/writer_posix.go
index f54a5d06..764bd97b 100644
--- a/cwriter/writer_posix.go
+++ b/cwriter/writer_posix.go
@@ -1,4 +1,4 @@
-// +build !windows
+// +build !windows,!wasm,!js
 
 package cwriter
 
diff --git a/cwriter/writer_wasm.go b/cwriter/writer_wasm.go
new file mode 100644
index 00000000..360841df
--- /dev/null
+++ b/cwriter/writer_wasm.go
@@ -0,0 +1,15 @@
+// +build wasm js
+
+package cwriter
+
+// Don't overwrite clearLines()
+
+// GetSize do nothing
+func GetSize(fd int) (width, height int, err error) {
+	return 0, 0, nil
+}
+
+// IsTerminal do nothing
+func IsTerminal(fd int) bool {
+	return true
+}