body keyup increasing each time

body keyup increasing each time

hi , i have a searchbox that search the database for me and return sth , i have attched the keyup event to this textbox and when i write something into it it return me the data that should return , its working pretty fine and its return me the data  , im using ajax into this


$('body').on("keyup"," #searchbox",function(e){ 
      $.ajax({type:"POST",url:"functions.php",data:{"searchcandida":"true","values":txt},success:function(data){

            if(data.trim() != ""){
                  
                  $('body').bind('keyup',function(event){
                        
                        if(event.keyCode == 40)// down arrows pushing
                        // dosth 
                        alert("hello there you are pushing bottom arrows");
                        });
                  }
            }
      });
 });

but the problem is here , that when i push the bottom arrow,down arrow, Pg Dn , on each time the keydown events increase , like if i click the down arrow for the first time it w'll do the alert one time at the second time it w'll do it two times at the third time it w'll do the alert for three time and so one 
i dont know why the key up events increseing on each time .