javascript - 通过jquery显示php json编码数组的值时出现未定义错误

Question

我正在尝试显示从 jquery post 接收到的数据。但它给我一个错误，说 undefined

我的 php json 编码数组是这样的。

[{"matId":"7","matName":"test","matBrand":"est","matPackaging":"1","matWidth":"434","matHeight":"23","matLength":"23","matWeight":"23","matArea":"23","matVolume":"23","matPerPack":"32","supplier1":"19","supplier2":"19","supplier3":"19","requiredInPhase":"","stockItem":"1"}]

然后在 jquery 中我试图警告这个值之一，但它给出错误“未定义”。

这是我的 jquery 代码

$('#matId').on('change', function() {
            var matId = $(this).val();
            $.post('<?php echo base_url() . 'display_mat_details'; ?>', {matId: matId}, function(redata) {
                var obj = $.parseJSON(redata);
                alert(obj.matId);
            });
        });

Answer 1

您的数据包含在 [] 中，这是一个数组。因此您需要使用 [0] 从数组中获取第一个对象

$('#matId').on('change', function() {
  var matId = $(this).val();
  $.post('<?php echo base_url() . '
    display_mat_details '; ?>', {
      matId: matId
    }, function(redata) {
      var obj = $.parseJSON(redata);
      alert(obj[0].matId);
    });
});

示例:

var str = [{"matId":"7","matName":"test","matBrand":"est","matPackaging":"1","matWidth":"434","matHeight":"23","matLength":"23","matWeight":"23","matArea":"23","matVolume":"23","matPerPack":"32","supplier1":"19","supplier2":"19","supplier3":"19","requiredInPhase":"","stockItem":"1"}];
alert(str[0].matId);