How to delete span content in jquery

In the development of web pages, we often need to perform dynamic operations on certain elements on the page, such as adding, modifying, deleting content, etc. For some static elements, we can modify them directly in the HTML code, but for some dynamic elements, we need to use tools such as JavaScript or jQuery to complete the operation. This article will focus on how to use jQuery to delete the span element content on the page.

1. What is jQuery?

First, we need to understand jQuery. jQuery is a JavaScript library that provides a series of functions and methods to simplify HTML document traversal, event handling, animation effects, and AJAX operations. By using jQuery, we can easily operate elements on the page.

2. Methods to delete the content of the span element

In jQuery, you can use the .empty() method or the .remove() method to delete the content of the span element.

1. Use the .empty() method

.empty() method can clear all child elements in the element, including text and HTML elements. For example, we have a span element:

<span id="demo">Hello World!</span>

We can empty its content using the following code:

$("#demo").empty();

.empty() method will only delete the element content, not the element itself. If you need to remove an element and its contents, use the .remove() method.

2. Use the .remove() method

The .remove() method can delete the specified element and all its child elements. For example, we have the following HTML code:

    <span id="demo">Hello World!</span>

We can remove the span element and its content using the following code:

$("#demo").remove();

.remove() method can remove the element itself as well as its content if only To remove the content of an element, use the .empty() method.

3. Examples of application scenarios

1. Delete a certain column in the table

In the table, if we want to delete a certain column, we can first select the column The header of the column, then use the .nextUntil() method to select the column that needs to be deleted, and finally use the .remove() method to delete the selected column.

For example, we have the following table:

<table>
    <thead>
        <tr>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>张三</td>
            <td>男</td>
            <td>25</td>
        </tr>
        <tr>
            <td>李四</td>
            <td>女</td>
            <td>23</td>
        </tr>
    </tbody>
</table>

If we want to delete the gender column, we can use the following code:

$('th:contains("性别")').nextUntil().addBack().remove();

2. Delete the default value in the input box

In forms, we often set default values, such as placeholders, etc. When the user starts typing, we need to clear the default value and display what the user entered. You can delete the default value of the input box through the following code:

$('input[type="text"]').focus(function(){
    if($(this).val() == $(this).attr('default_value')){
        $(this).val('');
    }
}).blur(function(){
    if($(this).val() == ''){
        $(this).val($(this).attr('default_value'));
    }
});

In the above code, we first select all input boxes of type text, and then determine whether the value of the input box is the default value when the input box gets focus. If so, clear the content of the input box; when the input box loses focus, if the value of the input box is empty, the default value is assigned to the value of the input box.

4. Summary

The above is the method and application scenarios of using jQuery to delete the span element content. By using jQuery, we can easily delete elements and their contents on the page to facilitate web development. It is worth noting that when using the .remove() method, pay attention to selecting the element range to avoid accidentally deleting other elements.

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