function change_tab(id)
{
  if(id==1)
  {
    document.getElementById('products_view_tabs_content_files').style.display = 'none';
    document.getElementById('tab_2').style.height = '28px';
    document.getElementById('tab_2').style.borderBottom = '1px solid #E8E8E8';
    document.getElementById('tab_2').style.color = '#676767';
    document.getElementById('tab_2').style.background = 'url(/images/tab_inactive_bg.gif) repeat-x';
    
    document.getElementById('products_view_tabs_content_realizations').style.display = 'none';
    document.getElementById('tab_3').style.height = '28px';
    document.getElementById('tab_3').style.borderBottom = '1px solid #E8E8E8';
    document.getElementById('tab_3').style.color = '#676767';
    document.getElementById('tab_3').style.background = 'url(/images/tab_inactive_bg.gif) repeat-x';
    
    document.getElementById('tab_1').style.borderBottom = '0px';
    document.getElementById('tab_1').style.height = '29px';
    document.getElementById('tab_1').style.color = '#000000';
    document.getElementById('tab_1').style.background = 'none';
    document.getElementById('products_view_tabs_content_specification').style.display = '';
  }
  else if(id==2)
  {
    document.getElementById('products_view_tabs_content_specification').style.display = 'none';
    document.getElementById('tab_1').style.borderBottom = '1px solid #E8E8E8';
    document.getElementById('tab_1').style.height = '28px';
    document.getElementById('tab_1').style.color = '#676767';
    document.getElementById('tab_1').style.background = 'url(/images/tab_inactive_bg.gif) repeat-x';
    
    document.getElementById('products_view_tabs_content_files').style.display = 'none';
    document.getElementById('tab_3').style.height = '28px';
    document.getElementById('tab_3').style.borderBottom = '1px solid #E8E8E8';
    document.getElementById('tab_3').style.color = '#676767';
    document.getElementById('tab_3').style.background = 'url(/images/tab_inactive_bg.gif) repeat-x';
    
    document.getElementById('tab_2').style.borderBottom = '0px';
    document.getElementById('tab_2').style.height = '29px';
    document.getElementById('tab_2').style.color = '#000000';
    document.getElementById('tab_2').style.background = 'none';
    document.getElementById('products_view_tabs_content_realizations').style.display = '';
  }
  else if(id==3)
  {
    document.getElementById('products_view_tabs_content_specification').style.display = 'none';
    document.getElementById('tab_1').style.borderBottom = '1px solid #E8E8E8';
    document.getElementById('tab_1').style.height = '28px';
    document.getElementById('tab_1').style.color = '#676767';
    document.getElementById('tab_1').style.background = 'url(/images/tab_inactive_bg.gif) repeat-x';
    
    document.getElementById('products_view_tabs_content_realizations').style.display = 'none';
    document.getElementById('tab_2').style.height = '28px';
    document.getElementById('tab_2').style.borderBottom = '1px solid #E8E8E8';
    document.getElementById('tab_2').style.color = '#676767';
    document.getElementById('tab_2').style.background = 'url(/images/tab_inactive_bg.gif) repeat-x';
    
    document.getElementById('tab_3').style.borderBottom = '0px';
    document.getElementById('tab_3').style.height = '29px';
    document.getElementById('tab_3').style.color = '#000000';
    document.getElementById('tab_3').style.background = 'none';
    document.getElementById('products_view_tabs_content_files').style.display = '';
  }
}