how can I pass ajax value to php variable ?

You store the data you want to send in the data attribute of your ajax call. In a previous project I had this in my ajax call type : {type_id : type } where type was a variable I got from jQuery using var type = $('#type').val()

Another attribute of the ajax call will be the URL. To wherever that URL is pointing that file needs to receive the data. And that's easy. In that PHP file, in my case it simply was $type_id = $_GET['type_id']

Now I have a PHP variable $type_id that held the value from the ajax call. In my case it was a select drop down and i was getting the id value of the select, which is why I was calling it type_id.

thank you so much for answer , it was useful