jQuery Auto Refresh Send Value Variable -

i want pass value of variable using jquery auto refresh :

var auto_refresh = setinterval ( function () { var p_box_sn = $("#p_box_sn").val();  $.ajaxsetup({ cache: false }); $('#counts').load('load.php?p_box_sn=p_box_sn').fadein("slow"); }, 1000 ); 

but show output : p_box_sn. wanted value var p_box_sn , sent load function. possible?

since p_box_sn variable, need concatenate using +:

$('#counts').load('load.php?p_box_sn=' + p_box_sn).fadein("slow");