viewport scale doesn't work after orientation change

I use the following function to rescale my viewport on iPad:

function rescale(scale){

 var headElements = document.getElementsByTagName("meta");

    for(var i = 0; i< headElements.length; i++){

    var theElement = headElements[i];

    if(theElement.name == "viewport"){

      theElement.content = "width=device-width, user-scalable=no, initial-scale=" + scale + ", maximum-scale=" + scale + ";";



    }     

  }

}

This works an unlimited number of times (in either portrait or landscape orientation), until I change the orientation of the device, when it ceases to work until i reload the page.

Is this a bug in iOS, or are there any workarounds?