Captcha Validation protects the website from spammers. It is used to identify robots or bots. Since you are a programmer, you know that spamming a website can easily be done using loops of different program languages.
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Untitled by Shantanu Jana (@shantanu-jana)
In the case of Captcha Validation, basically from two boxes and a button. A box will contain some pictures or some captcha code. You have to input in another box by looking at those characters. If you input incorrectly, your message will not be sent.
There is basically a display where random Captcha code can be seen. There is another input box to input the Captcha code. It has a submit button that will submit your input Captcha.
Step 1: Basic structure of Custom Captcha
The basic structure of Captcha Validation has been created using the following code. A box has been created here on the webpage.