Question

首先，我将陈述明显的，我是javascript，html和web开发工具的新手。

var labels = {{ labels|tojson|safe }};

使用console.log我能够看到标签console.log(JSON.stringify(labels));的内容输出：

[
    {"id":"1","image":"1-0.png","name":"","xMax":"4802","xMin":"4770","yMax":"156","yMin":"141"},
    {"id":"2","image":"1-0.png","name":"","xMax":"4895","xMin":"4810","yMax":"157","yMin":"141"},
    {"id":"3","image":"1-0.png","name":"","xMax":"4923","xMin":"4903","yMax":"156","yMin":"145"},
    {"id":"4","image":"1-0.png","name":"","xMax":"4956","xMin":"4931","yMax":"156","yMin":"145"}
]

它显然是一个字典列表，到目前为止一直很好，现在有新的元素我想在它运行时附加并且没有刷新页面手动，它应该自动更新，所以因为我有一些经验python，我很快想到了追加，就像那样：

labels.append({"id":labels.length + 1, 
               "name":"",
               "xMin":xMin,
               "xMax":xMax,
               "yMin":yMin,
               "yMax":yMax
              })

但它不起作用，我该怎么追加那条线？

Answer 1

labels是一个数组类型，因为它有

[{"id":"1","image":"1-0.png","name":"","xMax":"4802","xMin":"4770","yMax":"156","yMin":"141"},{"id":"2","image":"1-0.png","name":"","xMax":"4895","xMin":"4810","yMax":"157","yMin":"141"},{"id":"3","image":"1-0.png","name":"","xMax":"4923","xMin":"4903","yMax":"156","yMin":"145"},{"id":"4","image":"1-0.png","name":"","xMax":"4956","xMin":"4931","yMax":"156","yMin":"145"}]

因此，您需要使用labels.push(obj)在labels而非append()

中添加新对象

var labels = [{"id":"1","image":"1-0.png","name":"","xMax":"4802","xMin":"4770","yMax":"156","yMin":"141"},{"id":"2","image":"1-0.png","name":"","xMax":"4895","xMin":"4810","yMax":"157","yMin":"141"},{"id":"3","image":"1-0.png","name":"","xMax":"4923","xMin":"4903","yMax":"156","yMin":"145"},{"id":"4","image":"1-0.png","name":"","xMax":"4956","xMin":"4931","yMax":"156","yMin":"145"}]

var xMin = 1, xMax = 5, yMin = 3, yMax = 8;

labels.push({"id":labels.length + 1, "name":"", "xMin": xMin, "xMax":xMax, "yMin":yMin, "yMax":yMax});

console.log(labels);

Answer 2

Array.prototype.append()不存在。如果要添加Array.prototype.push()，则需要使用var labels = [{"id":"1","image":"1-0.png","name":"","xMax":"4802","xMin":"4770","yMax":"156","yMin":"141"},{"id":"2","image":"1-0.png","name":"","xMax":"4895","xMin":"4810","yMax":"157","yMin":"141"},{"id":"3","image":"1-0.png","name":"","xMax":"4923","xMin":"4903","yMax":"156","yMin":"145"},{"id":"4","image":"1-0.png","name":"","xMax":"4956","xMin":"4931","yMax":"156","yMin":"145"}]; console.log(labels); labels.push({"id":labels.length + 1, "name":"name", "xMin":'xMin', "xMax":'xMax', "yMin":'yMin', "yMax":'yMax'}); console.log(labels);：

像这样：

＆＃13;

select
  *
from
  artists as a
where
  exists (
    select
      *
    from
      event_artist as ea
    where
      ea.artist_id = a.id
  )

＆＃13;

我怎样才能在javascript中添加？

2 个答案: