What are the best HTML form elements and attributes to validate your code?

HTML forms are essential for collecting user input and sending data to a server. However, not all forms are created equal. Some forms may have errors, inconsistencies, or security risks that can affect the user experience and the data quality. To avoid these problems, you need to validate your HTML code and use the best form elements and attributes for your purpose. In this article, you will learn what validation means, why it is important, and how to use some of the most useful HTML form elements and attributes to validate your code.

1 What is validation?

Validation is the process of checking if your HTML code follows the rules and standards of the language. Validation can help you avoid syntax errors, improve accessibility, enhance compatibility, and ensure compliance with regulations. You can use online tools, such as the W3C Markup Validation Service, to validate your HTML code and fix any issues. Validation can also be done on the client-side (by the browser) or the server-side (by the web application) to verify the user input and the data format.

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Neeru Gangarh

CSE’27 UG @CTU🎓 | GSSoC'24 (Ranked 18th 🏅) | Open Source Contributor @SWOC'25 | WoB | Hacktoberfest'24 🍁 | HTML | CSS | JS | 100+ Days of DSA & JS 📚 | Learning React ⚛️
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Use <input> with attributes like required, type, pattern, min, max, and <select> with required for validation. For text, use <textarea> with maxlength. The <form> tag can disable validation with novalidate when needed.

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Rangel Paolo Cardoso Bomfim

Java Software Developer @IBM | Backend Developer | Spring Developer | Quarkus | Learning Polish by myself
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During your experience as a Software Developer, you'll encounter validation every day. Without it, the user could enter any value, and populate the database with irrelevant data, which in fact will not be helpful for the company to take metrics over the data. The point is the data your system must accept, the format of it, maybe text, numeric, alphanumeric, and so on, and the size for it, like the number of characters, maximum and minimum values, and also the pattern of characters, for instance in passwords. Each day, the leader of my team makes a point to emphasize the use of validation, which takes place both on the graphic interface, and the API or microservice that will handle the data.

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2 Why is validation important?

Validation is important for several reasons. First, validation can improve the user experience by preventing errors, ensuring consistency, and providing feedback. For example, if you use the required attribute on a form element, the browser will prevent the user from submitting the form without filling in the required field. Second, validation can improve the data quality by preventing invalid, incomplete, or malicious input. For example, if you use the type attribute on a form element, the browser will check if the input matches the expected data type, such as email, number, or date. Third, validation can improve the security by preventing cross-site scripting (XSS) attacks, SQL injection attacks, or other forms of code injection. For example, if you use the pattern attribute on a form element, the browser will check if the input matches a specific regular expression, such as a phone number or a password.

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3 How to use the

type attribute?

The type attribute specifies the data type of a form element, such as text , email , number , or date . The type attribute can help you validate your code by enabling the browser to perform automatic validation and display appropriate input controls and formats. For example, if you use the type="email" attribute on an <input> element, the browser will check if the input is a valid email address and display a keyboard with the @ symbol. The type attribute can also accept some values that are not data types, but provide specific functionalities, such as submit , reset , or hidden .

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4 How to use the

required attribute?

The required attribute specifies that a form element must be filled in before submitting the form. The required attribute can help you validate your code by ensuring that the user provides all the necessary information and preventing incomplete submissions. For example, if you use the required attribute on an <input> element, the browser will display a message or an indicator that the field is mandatory and prevent the form from being submitted until the field is filled in. The required attribute can be used on any form element that accepts user input, such as <input> , <select> , or <textarea> .

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Rangel Paolo Cardoso Bomfim

Java Software Developer @IBM | Backend Developer | Spring Developer | Quarkus | Learning Polish by myself
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If you've coded some HTML, just for fun or for a real project, you probably noticed that after trying to send a form that contains a required attribute in any of its fields, the field then displays a little message, that basically tells you the need to fill the form field with the required information. As you get more experience, you can even customize the appearance of the message, once each browser has a slightly different graphic design, it might not look so fancy for the final user. In summary, the required attribute ensures that an important and not nullable field of your form will be successfully submitted.

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5 How to use the

pattern attribute?

The pattern attribute specifies a regular expression that the input must match before submitting the form. A regular expression is a sequence of characters that defines a specific pattern or format, such as a phone number or a password. The pattern attribute can help you validate your code by allowing you to define custom rules and constraints for the input and preventing invalid or unwanted input. For example, if you use the pattern="[A-Za-z]{3,10}" attribute on an <input> element, the browser will check if the input consists of only letters and has a length between 3 and 10 characters. The pattern attribute can only be used on <input> elements that have a type="text" , type="search" , type="tel" , type="url" , type="email" , or type="password" .

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Oleg Tyshchenko 📈

Founder & CEO of Quantum Marketing Lab LLC | Search Engine Optimization Expert
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The pattern attribute allows you to limit the set of characters used, as well as determine the order in which they are used. For example, When using type="email" normally, the browser will consider options such as "login@domain" or "123%123@domain.com" to be valid. To fix this problem you can use pattern. In normal use of type="url" the browser will consider something like "abcd:efgh" to be valid. To allow only http: and https: you should also use pattern.

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6 How to use the

min , max , and step attributes?

The min , max , and step attributes specify the minimum, maximum, and step values for a form element that accepts numeric input, such as type="number" , type="range" , or type="date" . The min , max , and step attributes can help you validate your code by limiting the range and increment of the input and preventing out-of-bounds or invalid input. For example, if you use the min="0" , max="100" , and step="10" attributes on an <input> element with a type="range" , the browser will display a slider that allows the user to select a value between 0 and 100 with a step of 10. The min , max , and step attributes can also accept relative values, such as min="today" or step="any" .

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Mousa A.

Software Engineer | Full Stack .NET Developer | C# | Web API | Angular
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The min, max and step attributes are used with the input tag inside the form. Here a simplified example of How to use it: <form action="/action_page.php"> <input type="number" min="2" max="6" step="2"> <input type="submit"> </form> In this example, when you click on the submit button, if the number is not between 2 and 6 and not a multiple of 2, it will give you a validation error! In other words, the number should be 2 or 4 or 6! Note: The max, min and step attributes works with the following input types: number, range, date, datetime-local, month, time and week.

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7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

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What are the best HTML form elements and attributes to validate your code?

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1 What is validation?

2 Why is validation important?

3 How to use the

4 How to use the

5 How to use the

6 How to use the

7 Here’s what else to consider

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