backbone.js - Issue in pagination in backbone -

i want pagination in backbone. have selectbox , when click on want show sepcific number of data.

<div class="results right" >           <form>             <label for="results">results pr. page</label>             <select name="results" id="showselect">               <option value="25" >25</option>               <option value="50" >50</option>               <option value="100" >100</option>               <option value="500" >500</option>             </select>           </form>         </div> 

model

defaults : {                 id : null,                 created : null,                 timestamp : null               },  parse : function(response){                 response.id = response._id.$oid;                 response.created = response.created.$date;                 response.timestamp = response.timestamp.$date;                  return response;             }, 

this collection:

pagination : function(perpage, page) {                 page = page - 1;                 var collection = this;                 collection = _(collection.rest(perpage * page));                 collection = _(collection.first(perpage));                 return collection.map( function(model) {                     return model.tojson();                 });             }, 

and view in separate file: (uncompleted)

     events : {                              "change #messageselect" : "changedgroup",                          },         changedgroup : function(e){                         e.preventdefault();                         console.log("selector changed");                         this.currentpage = 1;                         this.selectedgroupid = $("#messageselect :selected").attr("value");                         console.log("id of select is", this.selectedgroupid);                          //resets current groups when changed.                         this.currentgroup = this.collection.get(this.selectedgroupid);                     },  renderrecentlist : function(groupid, pagetoload) {                     var banpage = pagetoload || this.currentbanspage ;                     console.log("load page", banpage);                     this.selectedgroup = this.collection.get(groupid);                 } 

to honset, not know how evaluate max page in view. did id of selector when user click on (the number of data want load e.g. 100, 50 etc) , created function evaluating max page load. how can number of data

 var maxpages = math.ceil(? / this.pagesize);                         console.log("max", maxpages);                         var pagetoload = this.currentpage + 1;                         console.log("load me page", pagetoload);                         if(pagetoload <= maxpages) this.renderrecentlist(this.selectedgroupid, pagetoload);                         else{                             console.log("no more pages load");                             this.setglobalmessage("no more pages load", "information");                         }                         return this; 

i suggest on server side. load items want show , if parameters change create new request.

so steps:

1. create service recives per page , page number parameters , returns corresponding items.
2. when user first enter page request default parameters , render items.
3. when user changes page or items per page new request , render items came server.