1. returnthis.pushStack([].sort.apply(this, arguments ),[]); 

what are they doing ? what is "sort.apply"? Anybody can convert that 
to plain coding or point to any link ?

1. jQuery.fn.sort = function() { 
             return this.pushStack( [].sort.apply( this, arguments ), []); 
         }; 
   
          function sortLastName(a,b){ 
              if (a.l_name == b.l_name){
                return 0;
              }
              return a.l_name> b.l_name ? 1 : -1; 
          }; 
           function sortLastNameDesc(a,b){ 
              return sortLastName(a,b) * -1; 
          };
         var people= [
         {
         "f_name": "john",
         "l_name": "doe",
         "sequence": "0",
         "title" : "president",
         "url" : "google.com",
         "color" : "333333",
         },
         {
         "f_name": "michael",
         "l_name": "goodyear",
         "sequence": "0",
         "title" : "general manager",
         "url" : "google.com",
         "color" : "333333",
         }]
   
         sorted=$(people).sort(sortLastNameDesc);