diff --git a/html/index.html b/html/index.html
index e2be90b..83f0012 100644
--- a/html/index.html
+++ b/html/index.html
@@ -12,6 +12,10 @@
         }
     </script>
     <script id="fragmentShader" type="x-shader/x-fragment">
+        #ifdef GL_ES
+        precision highp float;
+        #endif
+
         uniform float iTime;
         uniform vec2 iMouse;
         uniform vec2 iResolution;