Получите значение выбранного флажки jQuery
$('#checkbox_id:checked').val();
//if checkbox is selected than gets its value
M. Wasim Abbasi
$('#checkbox_id:checked').val();
//if checkbox is selected than gets its value$(":checkbox[value=4]").prop("checked","true");
$("#merge_button").click(function(event){
event.preventDefault();
var searchIDs = $("#find-table input:checkbox:checked").map(function(){
return $(this).val();
}).get(); // <----
console.log(searchIDs);
});