极客教程jQuery index()的例子
index()是jQuery中的一个内置方法，用于返回与选择器有关的指定元素的索引。
语法:
$(selector).index(element)
参数：它接受一个可选的参数 “element”，用来获取元素的位置。
返回值：它返回一个整数，表示指定元素的索引。
jQuery代码显示index()函数的工作：
代码 #1:
<!DOCTYPE html>
<html>
<head>
<script
src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js">
</script>
<script>
<!--jQuery code to demonstrate index function -->
// document ready
(document).ready(function() {
// if the list is clicked
("li").click(function() {
// index()
// to return the index of the clicked
// element of the list
document.getElementById("demo").innerHTML = "Clicked Index "
+ $(this).index();
});
});
</script>
</head>
<body>
<p>Click on the elements of the list to display their index
number with respect to the other elements in the list.</p>
<ul>
<li>Geeks</li>
<li>for</li>
<li>Geeks</li>
</ul>
<p id="demo"></p>
</body>
</html>
输出:
在点击列表中的任何元素之前
Click on the elements of the list to display their index number with
respect to the other elements in the list.
* Geeks
* for
* Geeks
在点击 “为 “之后-
Click on the elements of the list to display their index number with
respect with the other elements in the list.
* Geeks
* for
* Geeks
Clicked Index 1
代码 #2:
<!DOCTYPE html>
<html>
<head>
<script
src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js">
</script>
<script>
<!--jQuery code to demonstrate index function -->
// document ready
(document).ready(function() {
// if the list is clicked
("li").click(function() {
// index()
// to return the index of the clicked
// element of the list
document.getElementById("demo").innerHTML = "Clicked Index "
+ ((".myclass")).index($("#id"));
});
});
</script>
</head>
<body>
<p>Click on the elements of the list to display their index
number with respect with the other elements in the list.</p>
<ul>
<li>Geeks</li>
<li class="myclass">for</li>
<li class="myclass" id="id">Geeks</li>
</ul>
<p id="demo"></p>
</body>
</html>
输出:
在点击列表中的任何元素之前-
Click on the elements of the list to display their index number with
respect with the other elements in the list.
* Geeks
* for
* Geeks
在点击列表中的任何元素后–
Click on the elements of the list to display their index number with
respect with the other elements in the list.
* Geeks
* for
* Geeks
Clicked Index 1