jquery finds the first element

For front-end developers, they often need to find the order in which an element is arranged on the page, especially when elements are dynamically generated. At this time, using jQuery to easily find the serial number of the element on the page can help us complete the task quickly.

Below, we will introduce how to use jQuery to find the first element.

<li>eq() method

jQuery’s eq() method can help us find elements with specific index values. Its usage is:

$('selector').eq(index)

Among them, selector is the element selector we want to find, index is the sequence number of the element in the selector (starting from 0 count).

For example, we have the following HTML code:

<ul>
  <li>第一项</li>
  <li>第二项</li>
  <li>第三项</li>
</ul>

If we want to find the second <li> element, we can use the following code:

$('li').eq(1)

This will return a jQuery object containing the second <li> element.

<li>:eq pseudo-class selector

In addition to the eq() method, jQuery also provides a :eq pseudo-class Class selector, its usage is similar to the eq() method, but there is no need to call the method.

$('selector:eq(index)')

is the same as the eq() method, selector is the element selector we want to find, index is the element in the selector Serial number (counting from 0).

We can use the following code to find the same second <li> element:

$('li:eq(1)')

This will return an element containing the second < The jQuery object of the li> element.

<li>The find() method is used in combination with eq() or :eq

In addition to finding elements in the entire page, sometimes we need to find elements in a certain element (such as Find the child element at a specific position within a <div>). At this time, we can use the find() method in combination with the eq() or :eq pseudo-class selector.

For example, we have the following HTML code:

<div id="container">
  <div class="item">第一项</div>
  <div class="item">第二项</div>
  <div class="item">第三项</div>
</div>

If we want to find the <div>## with the id being container #For the second child element in the element, you can use the following code:

$('#container').find('.item').eq(1)

or:

$('#container .item:eq(1)')

Both methods will return an element containing the second

class The jQuery object of the <div> element of item.

Summary

As mentioned above, it is very simple to use jQuery to find the first element. We only need to use the

eq() method or :eq Pseudo class selector will do. If we need to find a child element at a specific position in an element, we can use the find() method in combination.

Through these methods, developers can easily determine the position of elements on the page and quickly complete tasks such as dynamically generating elements.

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