How to implement a simple verification code function in jquery

With the continuous development of the Internet, verification codes have become an indispensable part of the Internet. Verification codes are usually used to prevent websites from being maliciously attacked, to prevent malicious registration of robots and sending spam messages, etc. This article will introduce how to use jquery to implement a simple verification code.

1. What is verification code

Verification code, the full name is "Completely Automated Public Turing test to tell Computers and Humans Apart", which is a fully automated Turing test to distinguish computers and humans. As the name suggests, CAPTCHA is a test that differentiates between a real person and a machine. It generally consists of a simple text or number, with interference factors such as distortion, noise, etc., making it difficult for machines to recognize, but easier for humans to recognize.

2. Implementation ideas

Our verification code contains four digits. First, we need to prepare a text box for displaying the verification code and a text box for generating verification in HTML. code button.

<label>验证码：</label>
<input>
<button>换一张</button>

Among them, the text above the button can be changed according to your own needs. Next, we need to use jquery to add a click event to the button. When the button is clicked, a verification code is generated and displayed in the text box.

$(function() {
    $("#refresh").click(function() {
        var code = "";
        var codeLength = 4;//验证码的长度
        var checkCode = $("#captcha");
        var randomChar = new Array(
            '0','1','2','3','4','5','6','7','8','9');
        for(var i = 0; i <p>There are four parts in the code. First, we get the jquery object of the button through <code>$()</code>, and then add a click event to it, which is triggered when the button is clicked. Secondly, we need to generate a verification code. The code defines a string variable code with a length of 4 to store the generated verification code. Then, we defined an array randomChar, which stores ten numbers from 0 to 9 for generating verification codes. Next, we use the Math.floor() function to generate a random number from 0 to 9, then use index to obtain the corresponding number in the randomChar array, and add it to the code. Finally, we assign the generated verification code to the text box. </p><p>So far, we have completed simple verification code generation. However, some users may wish to see a different style of verification code, such as one containing letters and numbers, or one with noise elements. These can be modified as needed, such as adding letters, adding colors, adding interference lines, etc., to increase the difficulty of the verification code. </p><p>3. Implementation effect</p><p>The following is the effect of jquery simple verification code implemented in this article:</p><p><img src="https://img.php.cn/upload/article/000/000/068/168224358556159.png" alt="How to implement a simple verification code function in jquery" title="How to implement a simple verification code function in jquery"></p><p>4. Summary</p> <p>This article implements a simple verification code through jquery. This method is relatively simple and intuitive, and is more convenient to learn and apply. However, in actual applications, in order to increase the difficulty and security of the verification code, we also need to perform more complex processing, such as encrypting and storing the verification code. By studying this article, we can understand the basic ideas of jquery to implement verification codes, which will provide some help for us to further study and apply verification codes in the future. </p>

The above is the detailed content of How to implement a simple verification code function in jquery. For more information, please follow other related articles on the PHP Chinese website!