diff --git a/prometheus/get_pid.go b/prometheus/get_pid.go
new file mode 100644
index 000000000..8036aa1ac
--- /dev/null
+++ b/prometheus/get_pid.go
@@ -0,0 +1,25 @@
+// +build !js wasm
+
+// Copyright 2015 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+import "os"
+
+func getPIDFn() func() (int, error) {
+	pid := os.Getpid()
+	return func() (int, error) {
+		return pid, nil
+	}
+}
diff --git a/prometheus/get_pid_gopherjs.go b/prometheus/get_pid_gopherjs.go
new file mode 100644
index 000000000..baa7acc32
--- /dev/null
+++ b/prometheus/get_pid_gopherjs.go
@@ -0,0 +1,22 @@
+// +build js,!wasm
+
+// Copyright 2015 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+func getPIDFn() func() (int, error) {
+	return func() (int, error) {
+		return 1, nil
+	}
+}
diff --git a/prometheus/go_collector.go b/prometheus/go_collector.go
index 4d792aa29..8bf4f4011 100644
--- a/prometheus/go_collector.go
+++ b/prometheus/go_collector.go
@@ -246,7 +246,8 @@ func (c *baseGoCollector) Describe(ch chan<- *Desc) {
 // Collect returns the current state of all metrics of the collector.
 func (c *baseGoCollector) Collect(ch chan<- Metric) {
 	ch <- MustNewConstMetric(c.goroutinesDesc, GaugeValue, float64(runtime.NumGoroutine()))
-	n, _ := runtime.ThreadCreateProfile(nil)
+
+	n := getRuntimeNumThreads()
 	ch <- MustNewConstMetric(c.threadsDesc, GaugeValue, float64(n))
 
 	var stats debug.GCStats
diff --git a/prometheus/num_threads.go b/prometheus/num_threads.go
new file mode 100644
index 000000000..361310752
--- /dev/null
+++ b/prometheus/num_threads.go
@@ -0,0 +1,24 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !js wasm
+
+package prometheus
+
+import "runtime"
+
+// getRuntimeNumThreads returns the number of open OS threads.
+func getRuntimeNumThreads() float64 {
+	n, _ := runtime.ThreadCreateProfile(nil)
+	return float64(n)
+}
diff --git a/prometheus/num_threads_gopherjs.go b/prometheus/num_threads_gopherjs.go
new file mode 100644
index 000000000..771033a2f
--- /dev/null
+++ b/prometheus/num_threads_gopherjs.go
@@ -0,0 +1,21 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build js,!wasm
+
+package prometheus
+
+// getRuntimeNumThreads returns the number of open OS threads.
+func getRuntimeNumThreads() float64 {
+	return 1
+}
diff --git a/prometheus/process_collector.go b/prometheus/process_collector.go
index 930272579..8548dd18e 100644
--- a/prometheus/process_collector.go
+++ b/prometheus/process_collector.go
@@ -103,8 +103,7 @@ func NewProcessCollector(opts ProcessCollectorOpts) Collector {
 	}
 
 	if opts.PidFn == nil {
-		pid := os.Getpid()
-		c.pidFn = func() (int, error) { return pid, nil }
+		c.pidFn = getPIDFn()
 	} else {
 		c.pidFn = opts.PidFn
 	}
diff --git a/prometheus/process_collector_js.go b/prometheus/process_collector_js.go
new file mode 100644
index 000000000..2e2be1209
--- /dev/null
+++ b/prometheus/process_collector_js.go
@@ -0,0 +1,25 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build js
+
+package prometheus
+
+func canCollectProcess() bool {
+	return false
+}
+
+func (c *processCollector) processCollect(ch chan<- Metric) {
+	// noop on this platform
+	return
+}
diff --git a/prometheus/process_collector_other.go b/prometheus/process_collector_other.go
index 2dc3660da..c0152cdb6 100644
--- a/prometheus/process_collector_other.go
+++ b/prometheus/process_collector_other.go
@@ -11,8 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build !windows
-// +build !windows
+//go:build !windows && !js
+// +build !windows,!js
 
 package prometheus