Question

我知道为什么我变得不确定，但是我不知道如何解决。

试图放入null，但它以文本形式出现

var text ='{"employees":[' +
                '{"name":"Tony","mobile":"99221111","email":"tony@json.com"},' +
                '{"name":"Linda","mobile":"98981111","email":"linda@json.com"},' +
                '{"name":"Patrick","mobile":"90902222","email":"patrick@json.com"},' +
                '{"name":"Isabella","mobile":"99552222"}]}';
    obj = JSON.parse(text);
    for(var i in obj.employees)
    {
        document.getElementById("table").innerHTML += "<tr><td>" + obj.employees[i].name + "</td>" + "<td>" + obj.employees[i].mobile + "</td>" 
            + "<td>" + obj.employees[i].email + "</td></tr>";
    }

您好，对于Isabella来说，没有电子邮件，因此，当我遍历以在html上打印其详细信息时，我变得不确定，但是我期望Isabella表中的电子邮件部分为空。有办法解决吗？

Answer 1

您可以使用逻辑OR（JavaScript中的||），如果第一个值（电子邮件）为undefined，它将使用第二个值（在这种情况下为空字符串）：

var text = '{"employees":[' +
  '{"name":"Tony","mobile":"99221111","email":"tony@json.com"},' +
  '{"name":"Linda","mobile":"98981111","email":"linda@json.com"},' +
  '{"name":"Patrick","mobile":"90902222","email":"patrick@json.com"},' +
  '{"name":"Isabella","mobile":"99552222"}]}';
obj = JSON.parse(text);
for (var i in obj.employees) {
  document.getElementById("table").innerHTML += "<tr><td>" + obj.employees[i].name + "</td>" + "<td>" + obj.employees[i].mobile + "</td>" +
    "<td>" + (obj.employees[i].email || '') + "</td></tr>";
}

<table id="table"></table>

如何遍历并正确打印

1 个答案: