Ajax implements simple real-time verification function
This time I will show you how ajax should implement real-time verification. What are the precautions for ajax to implement real-time verification? The following is a practical case, let's take a look.
What is ajax
Ajax stands for "Asynchronous Javascript And XML" (Asynchronous JavaScript and XML), which refers to a web development technology for creating interactive web applications.
Ajax = Asynchronous JavaScript and XML (a subset of Standard Universal Markup Language).
Ajax is a technology for creating fast, dynamic web pages.
Ajax is a technology that allows you to update parts of a web page without reloading the entire page.
By exchanging a small amount of data with the server in the background, Ajax allows web pages to be updated asynchronously. This means that parts of a web page can be updated without reloading the entire page.
Traditional web pages (not using Ajax) must reload the entire web page if content needs to be updated.
This is Baidu’s definition of it, which is detailed enough.
One thing worth adding is the understanding of asynchronous. Asynchronous is relative to synchronization. Here they refer to the interaction mode between the server and the browser.
Synchronous, after each request is issued, the user operation is blocked and must require a response to be returned before continuing the operation. Asynchronous means that after sending a request, the user does not need to wait for a response. Everything is implemented by ajax, and the data can be partially updated without refreshing the web page. Improved communication efficiency between both ends.
Let’s have a small demo
Make a demo of a non-refresh verification form, enter the user name in the dialog box, and perform verification in the background, using ajax technology.
Project structure, use maven to build
login.jsp
1 2 3 4 5 6 |
|
Welcome to log in:
1 2 3 4 5 6 7 |
|
main.js
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 |
|
web.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 |
|
loginServlet.java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 |
|
start testing
Enter localhost:8888/login.jsp, and a pop-up window
will appear. Represents the successful introduction of js into jsp
Enter test data
in the input box Determined by the logic in the Servlet, return error message
Determined by the logic in the Servlet, success information is returned
As a result, ajax asynchronous requests have been initially implemented, meeting the requirements of real-time verification
Some small details
1. When using maven to build the project, pay attention to Project Structure -> Facets
. Set the paths of web.xml and webapp here. Idea will use
2. When introducing js, pay attention to Use relative paths for mapping, and use EL expression to turn on isELIgnored="false"·` to avoid no resolution.
I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!
Recommended reading:
Parcel.js Vue 2.x quick configuration packaging method
VueRouter’s navigation guard should how to use
The above is the detailed content of Ajax implements simple real-time verification function. For more information, please follow other related articles on the PHP Chinese website!

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