I have written this javascript

<script type="text/javascript"> 
  function toggle(user_id) { 
    e=document.getElementById('toggleUserinfo_'+user_id); 
    a=document.getElementById('displayUserinfo_'+user_id); 
    if (e.style.display=='block') { 
      e.style.display='none'; a.innerHTML='show'; 
    } else { 
      e.style.display='block'; a.innerHTML='hide'; 
    } 
  } 
</script>

but its working fine on one page not working on other. The same file is used on both, any ideas?