javascript - 统计元素在页面中出现的次数

Question

在 jquery 的帮助下，我能够动态添加/删除输入字段。但我在尝试计算标签数量 data-bind='personCount' 并在 html 中显示结果时遇到困难。例如，对于每个项目都显示 Person #1、Person #2、Person #3 等。我已经能够在选择下拉菜单中使用 items 来实现此操作。如何计算标签 data-bind='personCount', 显示Person #1` 等的次数？这是JSFIDDLE

Jquery

var template;

function Person() { //we use this as an object constructor.
    this.personCount= 0;
    this.firstName = '';
}

function renderItem() {
    template = template || $("[data-template=item]").html();
    var el = $("<div></div>").html(template);
    return el; // a new element with the template
}

function addItem() {
    var person = new Person(); // get the data
    var el = renderItem(); // get the element

    el.find("[data-bind=personCount]").keyup(function (e) {

    });

    el.find("[data-bind=firstName]").keyup(function (e) {
        person.firstName = this.value;
    });

    return {
        el: el,
        person: person
    }
}

var stuff = [];
$("[data-action='add']").click(function(e){
     var item = addItem();
     $("body").append(item.el);
     stuff.push(item);
});

$("[data-action='remove']").click(function(e){
      if(stuff.length > 1) {
          var item = stuff.pop()
          item.el.remove();
      }
});

     var item = addItem();
     $("body").append(item.el);
     stuff.push(item);


  });

HTML

<div>
<script type='text/template' data-template='item'>
<ul class="clonedSection">
<label data-bind='personCount' class="personCount">Person # {person_count}</label> 
    <li style="list-style-type: none;">
        <input type="text" data-bind='firstName' placeholder="First Name" required pattern="[a-zA-Z]+" />
    </li>
</ul>
</script>
<input type='button' value='add' data-action='add' />
<input type='button' value='remove' data-action='remove' />
</div>

Answer 1

写:

var count = $("body").find(".personCount[data-bind='personCount']").length;
$("body").find(".personCount[data-bind='personCount']:last").text("Person # {"+count+"}");

$("body").find(".personCount[data-bind='personCount']").length 将为您提供具有 personCount 类的元素数量> 和属性 data-bind='personCount'。

Updated fiddle here.