convert pages to layers

I have given two solutions (your question was not clear), try the below code:

1) All elements in the document will be changed to "Layer 1"

for (var idx = myDoc.allPageItems.length-1; idx >=0 ; idx--)
{
    var pageItem = myDoc.allPageItems[idx];
    pageItem.itemLayer = "Layer 1";
}

2) All the elements in a each an every page will be mapped to different to layer accordingly (I think you need this):

for(var p=0; p<myDoc.pages.length; p++)
{
    var myPageItems = myDoc.pages
.pageItems.everyItem().getElements();
    var myLayerPage = (p+1);
    for(var i=0;i<myPageItems.length;i++)
    {
        try{var myLayer = app.activeDocument.layers.add ({name: "Page " + myLayerPage});}catch(e){}        
        myPageItems.itemLayer = "Page " + myLayerPage;

    }
}