PHP product comparison function code sharing_php skills

The following is the code I wrote myself, and I will study and study it with everyone.

JS file called for product comparison (including product comparison box floating JS):

/*浮动窗口*/ 
(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'; 
  };   
})(); 
 
//添加显示对比框 
function addcompare(chk){ 
  $('#goods-compare').fadeIn().show(); 
  var count=$(".compare-box li").length; 
  if (count>2)//这里可以修改对比的数据哦 
  { 
    alert('产品比较最多选3种哦'); 
    return; 
  } 
 
  $.ajax({ 
    type: 'post', 
    url: 'ajax.php', 
    data: { 
      'action':'1', 
      'gid':chk.gid,//商品ID 
      'gname':chk.gname,//商品名称 
      'gtype':chk.gtype//商品类别，类别不同时不能比较 
    }, 
    cache: false, 
    async: false, 
    success: function(result) { 
      if(result!='') 
      { 
        alert(result); 
      }else{ 
        var url='http://www.lusen.com/product-'+chk.gid+'.html';//设置商品的链接地址 
        $(".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+"');\">删除</span></li>") 
        $("#comids").val($(".compare-box li").map(function(){//将对比的所有商品ID，赋值给#comids 
          return $(this).attr('id'); 
        }).get().join(",")); 
      } 
    } 
  }); 
} 
 
//删除对比产品 
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(",")); 
    } 
  }); 
  
} 
//清空对比产品 
function clearcompare() 
{   
  $.ajax({ 
    type: 'post', 
    url: 'ajax.php', 
    data: { 
      'action':'3' 
    }, 
    cache: false, 
    success: function(result) { 
      $(".compare-box").html(''); 
      $("#comids").val(''); 
    } 
  }); 
} 
//显示对比框 
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(); 
      } 
    } 
  }); 
  
} 
 
//点击关闭对比框 
$('.close-gc').click(function(){ 
  $('#goods-compare').fadeOut().hide(); 
}); 

Calling Ajax files for product comparison

<&#63;php 
function mb_unserialize($serial_str) { 
  $serial_str =stripslashes($serial_str); 
  return unserialize($serial_str); 
} 
if($_POST['action']=='1') {//add 
  if(isset($_COOKIE['gtype'])) { 
    if($_COOKIE['gtype']!=$_POST['gtype']) { 
      echo '对不起，您选择的是不同类别的产品无法加入对比，请选择同类产品或清空当前对比栏再选择。'; 
      return; 
    } 
  }else { 
    setcookie('gtype',$_POST['gtype']); 
  } 
  if(isset($_COOKIE['gid'])) { 
    $arr_str = $_COOKIE['gid']; 
    $arr=mb_unserialize($arr_str); 
    if(count($arr)>2) {//商品比较数量 
      echo "商品比较最多选3种"; 
      return; 
    } 
    foreach($arr as $val) { 
      if($val[0]==$_POST['gid']) { 
        echo "该商品已经加入对比框"; 
        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]}');\">删除</span></li>"; 
    } 
    echo $data; 
  }   
} 
&#63;> 

The above is the implementation code of the product comparison function. I hope you can study it carefully and discuss it together if you have good ideas.