当我尝试对它们进行排序时，如何在javascript中获取当前ul li的长度？

Question

<ul id="types" style="list-type:none;">

<li id="categories" style="list-type:none;">1
<ul>
    <li style="list-type:none;">1</li><br/>
    <li style="list-type:none;">1</li>
</ul>
</li>

<li id="categories" style="list-type:none;">2
<ul>
    <li style="list-type:none;">2</li><br/>
    <li style="list-type:none;">2</li>
</ul>
</li>

<li id="categories" style="list-type:none;">3
<ul>
    <li style="list-type:none;">3</li><br/>
    <li style="list-type:none;">3</li>
</ul>
</li>

</ul>

i am moving the li up and down ,when i am doing like this i have written the code for calling one jquery _mouseStop function(event,noPropagation))

in this function i am writing

var tagetNode = this.currentItem[0].parentNode.id

if (this.element[0].id == "categories") {
    var targetlistlength = document.getElementById(targetListId).getElementsByTagName("li").length;
    // var targetlistlength = this.parentNode.getElementsByTagName("li").length;
    var PageIds = "";
    for (var i = 0; i < targetlistlength; i++) {
        PageIds += document.getElementById(targetListId).getElementsByTagName("li")[i].getAttribute("value") + ",";
    }

}

when i am sorting the child li's the above function get called but it is always getting the first child ul of first li length only.. i want the current ul li's length which i am trying to sort

i have tried with the commented line also to get the length of li's but iam getting error as this.parentNode is undefined

anyone please suggest me what can i do

Answer 1

As there is no working demo available, you can check what you get when you use console.log($(this)); inside that function when mouseStop event occurs in console. If you get the expected li in the console then you can executing the following code to get the length of its parent's childs.

alert($(this).parent().children().length);

Answer 2

There mustn't be multiple elements with the same id. Try to replace them with classes or make them unique.

The if-condition could be the following if you have unique id's (eg categories-1, categories-2, ...)

if (this.element[0].id.match("^categories") != null) { ... }

Or if you use classes the if-condition could be:

if (this.element[0].className.match("(^| )categories( |$)") != null) { ... }