Make date select sticky across pages

analytics/index.xqy

@@ -106,7 +106,7 @@ return
           <td class="title"><span>
             {attribute data-ua {if($v) then $agent/*[1] else $agent }}
             {if($v) then attribute data-v {$agent/*[2]} else () }
-            <a href="/?ua={if($v) then $agent/*[1] else $agent}&amp;d=v">{if($v) then string-join($agent/*/text(), " ") else $agent}</a></span></td>
+            <a href="/?ua={if($v) then $agent/*[1] else $agent}&amp;d=v{if($b and $e) then concat('&amp;b=',$b,'&amp;e=',$e) else()}">{if($v) then string-join($agent/*/text(), " ") else $agent}</a></span></td>
           <td><div class="sparkline" id="sparkline{xdmp:random()}"></div></td>
           <td class="direction"><div></div></td>
           <td class="numeric"><span style="width: {xs:float(cts:frequency($agent) div $max-freq) * 100}%" class="bar">{format-number(cts:frequency($agent), "#,###")}</span></td>