<div class="card-item" item-id="<?php echo $item->id; ?>" id="card<?php echo $item->id; ?>">Текст</div>
<script>
$('.card-item').each(function(){
var item_id = $(this).attr('item-id');
});
</script>var a = 1234;
var b = 1235;
var cnt = [];
for(i in a){
if(b.indexOf(a[i]) != -1){
cnt[a[i]] = a[i];
}
}
console.log(cnt.length);var a = 1234;
var b = 1235;
var cnt = 0;
var x = a.lenght>b.lenght ? a:b;
for(i in x){
if(a[i]==b[i]){
cnt++;
}
}
console.log(cnt);