在JS中的函数内设置变量

Question

   var last = 0;

   function grabProducts(searchstring) {
       var last = 0;
       $.post('ajax/products', {
           method: 'search',
           string: searchstring,
           category: $('#search_category').val(),
           sort: $('.sort').val()
       }, function (data) {
           data = $.parseJSON(data);
           $.each(data, function (index, b) {
               last = "dada";
           });
       });
   }
   alert(last);

给我提醒"0".我怎样才能将变量设置为"dada"？

Answer 1

您无法进行类似的设置,因为它$.post()是异步的.您必须将"警报"放在您传递给的回调函数中$.post().

var last=0;
function grabProducts(searchstring) {
        var last=0;
        $.post('ajax/products', { method: 'search', string: searchstring, category: $('#search_category').val(), sort: $('.sort').val() }, function(data) {
            data = $.parseJSON(data);
            $.each(data, function(index, b) {
                last = "dada";

            });
            alert(last);
        });
      }

事实上,回调的重点是为您提供在HTTP请求完成时运行代码的方法.