How to determine whether the email address is valid in jquery

JQuery is a popular Javascript library, and its flexible and convenient syntax has made it one of the necessary tools for front-end development. In web applications, email addresses often need to be verified. So, how to use JQuery to determine whether the email address is valid? We will explore this issue below.

Before judging the email address, we need to first clarify what a valid email address is. A valid email address should comply with the following rules:

1. must contain the "@" symbol to separate the username and domain name.
2. Must contain a top-level domain name (such as .com, .cn, .org, etc.).
3. The domain name must contain at least one "." symbol to separate different domain names.

Now, let’s take a look at how to use JQuery for email verification.

Step one: Get the email address entered by the user

We need to use JQuery to get the email address entered by the user. Among them, we can use JQuery's val() method to get the value in the input box. The sample code is as follows:

var email = $('#email_input').val();

Among them, #email_input is the id of the user input box.

Step 2: Regular expression to verify email address

After obtaining the email address entered by the user, we need to use regular expressions to verify whether the email address is valid. JQuery uses RegExp objects for regular expression matching.

Before using regular expressions, we need to know the rules of regular expressions. A basic email address regular expression is as follows:

var emailPattern = /^([a-z0-9_\.-]+)@([\da-z\.-]+)\.([a-z\.]{2,6})$/;

where the regular expression is enclosed in a slash (/). It contains three parts, namely:

1. Username: contains lowercase letters, numbers, underlines, dots, and dashes, and can appear repeatedly.
2. Domain name: Contains lowercase letters, numbers, dots, and dashes, and can appear repeatedly.
3. Top-level domain name: Contains lowercase letters and dots.

The regular expression verification code is as follows:

if(emailPattern.test(email)){
  // valid email
} else {
  // invalid email
}

Among them, the test() method is used to check whether a string matches a certain pattern. The test() method will return true if the email address matches the pattern, false otherwise.

Step 3: Display the verification results

After checking the email address entered by the user, we need to display the verification results to the user. You can use JQuery's text() or html() method to display the validation results. The sample code is as follows:

if(emailPattern.test(email)){
  $('#email_validation_message').text('该邮箱地址有效！');
} else {
  $('#email_validation_message').text('该邮箱地址无效！');
}

Where, #email_validation_message is the id of the HTML element used to display the verification results.

Summary

It’s very simple to use JQuery to determine whether an email address is valid. We just need to get the email address entered by the user and verify it using regular expressions. If the verification result is true, it means that the email address is valid; otherwise, it means that the email address is invalid. At the same time, we can also use JQuery to display the verification results so that users can understand the verification results intuitively.

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