diff --git a/vertices_js.go b/vertices_js.go
new file mode 100644
index 000000000..4252d8bc7
--- /dev/null
+++ b/vertices_js.go
@@ -0,0 +1,95 @@
+// Copyright 2016 The Ebiten 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 ebiten
+
+import (
+	"github.com/gopherjs/gopherjs/js"
+	"github.com/hajimehoshi/ebiten/internal/graphics"
+)
+
+func vertices(parts ImageParts, width, height int, geo *GeoM) []float32 {
+	// TODO: This function should be in graphics package?
+	totalSize := graphics.QuadVertexSizeInBytes() / 4
+	l := parts.Len()
+	vs := js.Global.Get("Float32Array").New(l * totalSize)
+	g0 := geo.Element(0, 0)
+	g1 := geo.Element(0, 1)
+	g2 := geo.Element(1, 0)
+	g3 := geo.Element(1, 1)
+	g4 := geo.Element(0, 2)
+	g5 := geo.Element(1, 2)
+	w := 1.0
+	h := 1.0
+	for w < float64(width) {
+		w *= 2
+	}
+	for h < float64(height) {
+		h *= 2
+	}
+	n := 0
+	for i := 0; i < l; i++ {
+		dx0, dy0, dx1, dy1 := parts.Dst(i)
+		sx0, sy0, sx1, sy1 := parts.Src(i)
+		u0, v0, u1, v1 := float64(sx0)/w, float64(sy0)/h, float64(sx1)/w, float64(sy1)/h
+		vs.SetIndex(n, dx0)
+		vs.SetIndex(n+1, dy0)
+		vs.SetIndex(n+2, u0)
+		vs.SetIndex(n+3, v0)
+		vs.SetIndex(n+4, g0)
+		vs.SetIndex(n+5, g1)
+		vs.SetIndex(n+6, g2)
+		vs.SetIndex(n+7, g3)
+		vs.SetIndex(n+8, g4)
+		vs.SetIndex(n+9, g5)
+
+		vs.SetIndex(n+10, dx1)
+		vs.SetIndex(n+11, dy0)
+		vs.SetIndex(n+12, u1)
+		vs.SetIndex(n+13, v0)
+		vs.SetIndex(n+14, g0)
+		vs.SetIndex(n+15, g1)
+		vs.SetIndex(n+16, g2)
+		vs.SetIndex(n+17, g3)
+		vs.SetIndex(n+18, g4)
+		vs.SetIndex(n+19, g5)
+
+		vs.SetIndex(n+20, dx0)
+		vs.SetIndex(n+21, dy1)
+		vs.SetIndex(n+22, u0)
+		vs.SetIndex(n+23, v1)
+		vs.SetIndex(n+24, g0)
+		vs.SetIndex(n+25, g1)
+		vs.SetIndex(n+26, g2)
+		vs.SetIndex(n+27, g3)
+		vs.SetIndex(n+28, g4)
+		vs.SetIndex(n+29, g5)
+
+		vs.SetIndex(n+30, dx1)
+		vs.SetIndex(n+31, dy1)
+		vs.SetIndex(n+32, u1)
+		vs.SetIndex(n+33, v1)
+		vs.SetIndex(n+34, g0)
+		vs.SetIndex(n+35, g1)
+		vs.SetIndex(n+36, g2)
+		vs.SetIndex(n+37, g3)
+		vs.SetIndex(n+38, g4)
+		vs.SetIndex(n+39, g5)
+
+		n += totalSize
+	}
+	return vs.Interface().([]float32)
+}
diff --git a/vertices.go b/vertices_nojs.go
similarity index 59%
rename from vertices.go
rename to vertices_nojs.go
index b81474e92..f5f2a96c8 100644
--- a/vertices.go
+++ b/vertices_nojs.go
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !js
+
 package ebiten
 
 import (
@@ -21,16 +23,14 @@ import (
 func vertices(parts ImageParts, width, height int, geo *GeoM) []float32 {
 	// TODO: This function should be in graphics package?
 	totalSize := graphics.QuadVertexSizeInBytes() / 4
-	oneSize := totalSize / 4
 	l := parts.Len()
 	vs := make([]float32, l*totalSize)
-	geos := []float32{
-		float32(geo.Element(0, 0)),
-		float32(geo.Element(0, 1)),
-		float32(geo.Element(1, 0)),
-		float32(geo.Element(1, 1)),
-		float32(geo.Element(0, 2)),
-		float32(geo.Element(1, 2))}
+	g0 := float32(geo.Element(0, 0))
+	g1 := float32(geo.Element(0, 1))
+	g2 := float32(geo.Element(1, 0))
+	g3 := float32(geo.Element(1, 1))
+	g4 := float32(geo.Element(0, 2))
+	g5 := float32(geo.Element(1, 2))
 	w := float32(1)
 	h := float32(1)
 	for w < float32(width) {
@@ -39,43 +39,57 @@ func vertices(parts ImageParts, width, height int, geo *GeoM) []float32 {
 	for h < float32(height) {
 		h *= 2
 	}
+	n := 0
 	for i := 0; i < l; i++ {
 		dx0, dy0, dx1, dy1 := parts.Dst(i)
 		x0, y0, x1, y1 := float32(dx0), float32(dy0), float32(dx1), float32(dy1)
 		sx0, sy0, sx1, sy1 := parts.Src(i)
 		u0, v0, u1, v1 := float32(sx0)/w, float32(sy0)/h, float32(sx1)/w, float32(sy1)/h
-		offset := i * totalSize
-		vs[offset] = x0
-		vs[offset+1] = y0
-		vs[offset+2] = u0
-		vs[offset+3] = v0
-		for j, g := range geos {
-			vs[offset+4+j] = g
-		}
-		offset += oneSize
-		vs[offset] = x1
-		vs[offset+1] = y0
-		vs[offset+2] = u1
-		vs[offset+3] = v0
-		for j, g := range geos {
-			vs[offset+4+j] = g
-		}
-		offset += oneSize
-		vs[offset] = x0
-		vs[offset+1] = y1
-		vs[offset+2] = u0
-		vs[offset+3] = v1
-		for j, g := range geos {
-			vs[offset+4+j] = g
-		}
-		offset += oneSize
-		vs[offset] = x1
-		vs[offset+1] = y1
-		vs[offset+2] = u1
-		vs[offset+3] = v1
-		for j, g := range geos {
-			vs[offset+4+j] = g
-		}
+		vs[n] = x0
+		vs[n+1] = y0
+		vs[n+2] = u0
+		vs[n+3] = v0
+		vs[n+4] = g0
+		vs[n+5] = g1
+		vs[n+6] = g2
+		vs[n+7] = g3
+		vs[n+8] = g4
+		vs[n+9] = g5
+
+		vs[n+10] = x1
+		vs[n+11] = y0
+		vs[n+12] = u1
+		vs[n+13] = v0
+		vs[n+14] = g0
+		vs[n+15] = g1
+		vs[n+16] = g2
+		vs[n+17] = g3
+		vs[n+18] = g4
+		vs[n+19] = g5
+
+		vs[n+20] = x0
+		vs[n+21] = y1
+		vs[n+22] = u0
+		vs[n+23] = v1
+		vs[n+24] = g0
+		vs[n+25] = g1
+		vs[n+26] = g2
+		vs[n+27] = g3
+		vs[n+28] = g4
+		vs[n+29] = g5
+
+		vs[n+30] = x1
+		vs[n+31] = y1
+		vs[n+32] = u1
+		vs[n+33] = v1
+		vs[n+34] = g0
+		vs[n+35] = g1
+		vs[n+36] = g2
+		vs[n+37] = g3
+		vs[n+38] = g4
+		vs[n+39] = g5
+
+		n += totalSize
 	}
 	return vs
 }