Пример функции сравнения товаров, реализованной с помощью PHP + ajax

/*Floating window*/
(function(){
 var n=10;
 var obj=document.getElementById("goods-compare");
 if(!obj){
  return false;
 }
 var x=0;
 window.onscroll=function(){
  obj.style.top=(document.body.scrollTop||document.documentElement.scrollTop)+n+'px';
 };
 window.onresize=function(){
  obj.style.top=(document.body.scrollTop||document.documentElement.scrollTop)+n+'px';
 };
})();
//Add display contrast box
function addcompare(chk){
 $('#goods-compare').fadeIn().show();
 var count=$(".compare-box li").length;
 If (count > 2) // you can modify the comparison data here
 {
  Alert ('select 3 products at most for product comparison ');
  return;
 }
 $.ajax({
  type: 'post',
  url: 'ajax.php',
  data: {
   'action':'1',
   'GID': chk.gid, // commodity ID
   'gname': chk.gname, // commodity name
   'gType': chk. GType // product categories cannot be compared when they are different
  },
  cache: false,
  async: false,
  success: function(result) {
   if(result!='')
   {
    alert(result);
   }else{
    Var url ='http://www.lusen.com/product - '+ chk. GID +'. HTML '; // set the link address of the product
    $(". Compare box"). Append ("< Li class ='Division Clearfix 'id ='" + chk. GID + "') < div class ='span-3' > a href = '" + URL + "' target = '[blank' title = '" + chk. Gname + "'" '+ chk. Gname + "' < / a > < div > < span onclick =" removecompare ('"+ chk. GID +"'); \ "> delete < / span > < li >")
    $("comids"). Val ($(". Compare box Li"). Map (function() {// assign all commodity IDs of comparison to "comids"
     return $(this).attr('id');
    }).get().join(","));
   }
  }
 });
}
//Delete comparison products
function removecompare(id)
{
 $.ajax({
  type: 'post',
  url: 'ajax.php',
  data: {
   'action':'2',
   'gid':id
  },
  cache: false,
  success: function(result) {
   $("#"+id).remove();
   $("#comids").val($(".compare-box li").map(function(){
    return $(this).attr('id');
   }).get().join(","));
  }
 });
}
//Empty comparison products
function clearcompare()
{
 $.ajax({
  type: 'post',
  url: 'ajax.php',
  data: {
   'action':'3'
  },
  cache: false,
  success: function(result) {
   $(".compare-box").html('');
   $("#comids").val('');
  }
 });
}
//Show contrast box
function showcompare()
{
 $.ajax({
  type: 'post',
  url: 'ajax.php',
  data: {
   'action':'4'
  },
  success: function(result) {
   if(result){
    $(".compare-box").append(result);
    $("#comids").val($(".compare-box li").map(function(){
     return $(this).attr('id');
    }).get().join(","));
    $('#goods-compare').fadeIn().show();
   }
  }
 });
}
//Click to close the comparison box
$('.close-gc').click(function(){
 $('#goods-compare').fadeOut().hide();
});

 2) {// product comparison quantity
   Echo "select at most 3 kinds of goods for comparison";
   return;
  }
  foreach($arr as $val) {
   if($val[0]==$_POST['gid']) {
    Echo "the product has been added to the comparison box";
    return;
   }
  }
  $info=array($_POST['gid'],$_POST['gname'],$_POST['gtype']);
  $arr[]=$info;
  $arr_str=serialize($arr);
  setcookie('gid',$arr_str);
 }else {
  $info=array($_POST['gid'],$_POST['gname'],$_POST['gtype']);
  $arr[]=$info;
  $arr_str=serialize($arr);
  setcookie('gid',$arr_str);
 }
}else if($_POST['action']=='2') {//delone
 $id=$_POST['gid'];
 $arr_str = $_COOKIE['gid'];
 $arr=mb_unserialize($arr_str);
 foreach($arr as $key=>$val) {
  if($val[0]==$id) {
   unset ($arr[$key]);
  }
 }
 $arr_str=serialize($arr);
 setcookie('gid',$arr_str);
}else if($_POST['action']=='3') {//delall
 setcookie('gid','');
 setcookie('gtype','');
}else if($_POST['action']=='4') {//showlist
 if(isset($_COOKIE['gid'])) {
  $data='';
  $arr_str = $_COOKIE['gid'];
  $arr=mb_unserialize($arr_str);
  foreach ($arr as $val){
   $url="http://www.lusen.com/product-".$val[0].".html";
   $data. = "< Li id = '{$Val [0]}' class ='Division Clearfix ': < div class ='span-3' > a href = '{$URL}' target = '[blank' title = '{$Val [1]}' {$Val [1]}) < / a > < div > < span onclick = \" removecompare ('{$Val [0]}'); \ "> delete < / span > < / Li >";
  }
  echo $data;
 }
}
?>