How to do page navigation for many, many pages? Logarithmic page navigation

Question

What\'s the best way of displaying page navigation for many, many pages?

(Initially this was posted as a how-to tip with my answer included in the question. I\'ve

Answer 1

Here's my solution - use "Logarithmic Page Navigation":

This can be achieved by having page numbers distributed logarithmically, according to distance from either the endpoints or the current page. Here's an example of what I mean:

1 2 3 4 5 6 . 10 . 20 . 30 . 40 . 50 .. 100 .. 200 . 210 . 220 . 230 . 240 . 250 . 252 253 254 255 256 257 258 259 260 261 262 . 270 . 280 . 290 . 300 . 310 .. 400 .. 500 .. 600 .. 700 .. 800 .. 900 .. 950 . 960 . 970 . 980 . 990 . 995 996 997 998 999 1000

Notice how in the gaps, numbering goes from 1s, to 10s, to 100s (etc.). (I use powers of 10, but in principle you could use a different scheme - powers of 2, say).

I wrote some code that does this back in 2004, and thought I'd share it here. There are PHP and ASP versions, but the logic ought to be simple to translate into any language. Note that the bit at the bottom (in both cases) just displays some examples. Obviously the formatting will need customization to match your webpage (or application), so it's pretty basic here. Alter LINKS_PER_STEP in paginationHTML to determine how many numbers get displayed before the step size increases, as you move away from the endpoints or current page.

For a more compact output you could also consider altering the code so that the numbering is not "dense" around the endpoints (i.e. dense only around the current page).

Here's the code:

PHP version:

' . $p . '';
  return '' . $p . '';
}


// Used by paginationHTML below...
function paginationGap($p1, $p2)
{
  $x = $p2-$p1;
  if ($x==0) return '';
  if ($x==1) return ' ';
  if ($x<=10) return ' . ';
  if ($x<=100) return ' .. ';
  return ' ... ';
}


// URL requires the $page number be appended to it.
// e.g. it should end in '&page=' or something similar.
function paginationHTML($page, $lastPage, $URL)
{
  $LINKS_PER_STEP = 5;

  // Nav buttons

  if ($page>1)
    $result = '
 ' .
              '
';
  else $result = ' ';

  $result .= '  ' . $page . '  ';
  if ($page<$lastPage)
    $result .= '
 ' .
               '
';
  else $result .= ' ';
  $result .= "
";

  // Now calculate page links...

  $lastp1 = 1;
  $lastp2 = $page;
  $p1 = 1;
  $p2 = $page;
  $c1 = $LINKS_PER_STEP+1;
  $c2 = $LINKS_PER_STEP+1;
  $s1 = '';
  $s2 = '';
  $step = 1;
  while (true)
  {
    if ($c1>=$c2)
    {
      $s1 .= paginationGap($lastp1,$p1) . paginationLink($p1,$page,$URL);
      $lastp1 = $p1;
      $p1 += $step;
      $c1--;
    }
    else
    {
      $s2 = paginationLink($p2,$page,$URL) . paginationGap($p2,$lastp2) . $s2;
      $lastp2 = $p2;
      $p2 -= $step;
      $c2--;
    }
    if ($c2==0)
    {
      $step *= 10;
      $p1 += $step-1;         // Round UP to nearest multiple of $step
      $p1 -= ($p1 % $step);
      $p2 -= ($p2 % $step);   // Round DOWN to nearest multiple of $step
      $c1 = $LINKS_PER_STEP;
      $c2 = $LINKS_PER_STEP;
    }
    if ($p1>$p2)
    {
      $result .= $s1 . paginationGap($lastp1,$lastp2) . $s2;
      if (($lastp2>$page)||($page>=$lastPage)) return $result;
      $lastp1 = $page;
      $lastp2 = $lastPage;
      $p1 = $page+1;
      $p2 = $lastPage;
      $c1 = $LINKS_PER_STEP;
      $c2 = $LINKS_PER_STEP+1;
      $s1 = '';
      $s2 = '';
      $step = 1;
    }
  }
}

?>

ASP version:

<%

' Used by paginationHTML below...
Function paginationLink(p, page, URL)
  if p=page then
    paginationLink = "" & p & ""
  else
    paginationLink = "" & p & ""
  end if
End Function


' Used by paginationHTML below...
Function paginationGap(p1, p2)
  Dim x
  x = p2-p1
  if x=0 then
    paginationGap = ""
  elseif x=1 then
    paginationGap = " "
  elseif x<=10 then
    paginationGap = " . "
  elseif x<=100 then
    paginationGap = " .. "
  else
    paginationGap = " ... "
  end if
End Function


' URL requires the page number be appended to it.
' e.g. it should end in "&page=" or something similar.
Function paginationHTML(page, lastPage, URL)
  const LINKS_PER_STEP = 5
  Dim p1, p2, c1, c2, s1, s2, lastp1, lastp2, step

  ' Nav buttons
  if page>1 then
    paginationHTML = "
 " & _
                    "
"
  else
    paginationHTML = " "
  end if
  paginationHTML = paginationHTML & "  " & page & "  "
  if page " & _
                                    "
"
  else
    paginationHTML = paginationHTML & " "
  end if
  paginationHTML = paginationHTML & "
"

  ' Now calculate page links...

  lastp1 = 1
  lastp2 = page
  p1 = 1
  p2 = page
  c1 = LINKS_PER_STEP+1
  c2 = LINKS_PER_STEP+1
  s1 = ""
  s2 = ""
  step = 1
  do
    if c1>=c2 then
      s1 = s1 & paginationGap(lastp1, p1) & paginationLink(p1, page, URL)
      lastp1 = p1
      p1 = p1+step
      c1 = c1-1
    else
      s2 = paginationLink(p2, page, URL) & paginationGap(p2, lastp2) & s2
      lastp2 = p2
      p2 = p2-step
      c2 = c2-1
    end if
    if c2=0 then
      step = step*10
      p1 = p1+step-1         ' Round UP to nearest multiple of step
      p1 = p1-(p1 mod step)
      p2 = p2-(p2 mod step)  ' Round DOWN to nearest multiple of step
      c1 = LINKS_PER_STEP
      c2 = LINKS_PER_STEP
    end if
    if p1>p2 then
      paginationHTML = paginationHTML & s1 & paginationGap(lastp1, lastp2) & s2
      if (lastp2>page) or (page>=lastPage) then exit do
      lastp1 = page
      lastp2 = lastPage
      p1 = page+1
      p2 = lastPage
      c1 = LINKS_PER_STEP
      c2 = LINKS_PER_STEP+1
      s1 = ""
      s2 = ""
      step = 1
    end if
  loop
End Function

%>






<%=paginationHTML(1,1,"?page=")%>





<%=paginationHTML(2,3,"?page=")%>





<%=paginationHTML(3,3,"?page=")%>





<%=paginationHTML(73,100,"?page=")%>





<%=paginationHTML(4,100,"?page=")%>





<%=paginationHTML(257,1000,"?page=")%>





<%=paginationHTML(7062,10555,"?page=")%>





<%=paginationHTML(22080,503456,"?page=")%>

Javascript version (within complete test page):

  
  
  


  
Select number of pages:      and records per page:       

  


  

    
Go to page:  
    
 
    

    
 
    

  

  
Column Heading...



  

    
Go to page: