Untitled

<head>
    <script>
    var iWidth=1270;
    var map; .....
    </script>
   </head>

<body>
<div id="map" style="width: "+iWidth.ToString()+"px; height: 700px">
</div>

<head>
  <script>
    var iWidth=1270;
    var map; .....
  </script>
</head>

<body>
  <div id="map" style="height: 700px">
  </div>
  <script>
    document.getElementById("map").style.width = iWidth + "px";
  </script>
</body>