Simple example _ javascript tips for determining whether the user input value is null in js

This article mainly introduces a simple example of determining whether the user input value is null in js. If you need a friend, you can refer to it, it is expected to help you determine whether the user input value is null in js. there is nothing to write about. but I wrote it. the reason is that I think that my code is well written for your reference.

This is taken from the user registration page in one of my projects. For most people, this is almost 100% of their experiences.
Paste the Code. These codes are all written in js. It is not difficult and easy to understand. You only need to differentiate the two js classes.
Code of the front-end page: reguser. aspx

The Code is as follows:

<% @ Page language = "c #" Codebehind = "RegUser. aspx. cs" AutoEventWireup = "false" Inherits = "Enterprise. Web. RegUser" %>



User Registration