<script>
  var selectors = ['#splitter-sidebar','.vsplitbar', '#splitter-button']; 
  AJS.$.each(selectors, function(){ 
    AJS.$(''+this).hide(); 
  });
  AJS.$('#splitter-content').css({'width':'100%', 'left':'0'});
<style type="text/css">
#header 
{
display:none !important;
}
</style>
</script>