meta viewport

<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="viewport" content="width=device-width, initial-scale=1.0">

 <meta name="viewport" content="width=device-width, initial-scale=1">// viewport for web responsive design.. 

<meta name="viewport" content="width=device-width, initial-scale=1.0">

 <meta name="viewport" content="width=device-width, user-scalable=no">