Most web applications heavily rely on CSS and JavaScript code to deliver interactive, visually appealing, and user-friendly experiences. However, a single error in these codes can lead to inconsistencies like poor layout and security vulnerabilities.
That’s why the reason why developers always prioritize validating both JavaScript and CSS codes. To ensure maximum efficiency, they make use of different techniques and specialized tools.
In this detailed blog post, we are going to discuss both techniques and tools in detail. So, hang around with us till the end.
Techniques for Performing JavaScript & CSS Validations
Here are some of the proven techniques for effective JavaScript and CSS validation. To better understand this, we will discuss both JavaScript and CSS validation techniques separately.
Let’s start with JavaScript first:
1. Built-in HTML 5 Validation
Most of you may know that HTML5 provides built-in form validation features. These significantly assist in preventing invalid inputs before submitting the data.
This technique simplifies client-side validation without requiring the JavaScript code. Below, we have listed some of its notable validation features or attributes:
- Required Attribute – This one helps in ensuring that the field is not left empty.
- Pattern-matching – It allows developers to define regular expressions for input validation.
- Type-based validation – It specifies different inputs such as email, number, URL, and many more.
- Mix/Max attributes – This helps developers control the allowed range for numerical inputs.
Now, let’s understand this with a proper example. Below is the code that will prevent the form submission if the email field is either empty or invalid.
<form id="exampleForm">
<input type="email" required placeholder="Enter your email">
<input type="submit" value="Submit">
</form>It is important to note that HTML5 validation also has some limitations. For instance, it only works on modern browsers and doesn’t fulfill complex validation needs.
2. Regular Expressions Validation
The regular expressions provide a fast yet accurate way to validate different input patterns including:
- Emails
- Passwords
- Phone numbers
Many more.
The good thing about this technique is that it can be easily implemented on all browsers and offers excellent flexibility in defining different input patterns.
For a better understanding, we are also mentioning an example code below, do give it a look:
function validateEmail(email) {
let regex = /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/;
return regex.test(email);
}
console.log(validateEmail("[email protected]")); // Returns true
console.log(validateEmail("invalid-email")); // Returns falseRemember, for real-time validation, developers need to provide additional JavaScript to get the job done.
3. Event-based Validation
Last but not least, we have an event-based validation technique. JavaScript allows real-time validation by attaching event listeners to the form fields. This method significantly improves the overall experience by providing instant feedback.
Apart from that, event-based validation also helps in reducing the server-side workload.
document.getElementById("username").addEventListener("keyup", function () {
let username = this.value;
if (username.length < 5) {
this.style.borderColor = "red";
} else {
this.style.borderColor = "green";
}
});One thing to keep in mind about this technique is that it can be easily bypassed if JavaScript is disabled on the browser.
Proven CSS Validation Techniques:
When it comes to validating the CSS code, these are a few proven techniques that developers can consider following:
1. CSS Pseudo-classes
The Pseudo classes define special states of elements and help in stylish dynamic interactions. Using them properly is highly crucial to achieve consistency and accessibility across different browsers.
Here are some useful CSS Pseudo-classes, along with their use cases.
- :hover – Styles an element when hovered over.
- :focus – Efficiently applies style when an element is focused.
- :nth-child (n) – Target specific child elements dynamically.
Here is the example code for Pseudo-classes:
button:hover {
background-color: #007bff;
color: white;
}
input:focus {
border-color: #ff5733;
outline: none;
}Please note that some Pseudo-classes have limited browser support. So, use them properly and carefully.
2. Preprocessor Validation (SASS, LESS, PostCSS)
If you are using preprocessors like SASS, LESS, etc., then it is essential to validate the compiled CSS to prevent bugs in the output styling.
Now the question arises here is how exactly to validate. There is no need to look around as we have got you covered.
A Sass lint can be used for Sass specific syntax checking. You can run the following code to check a Saas file for errors:
npx sass-lint '**/*.scss' -vWhereas Lesshint is a tool that will be useful for LESS stylesheets.
3. Cross-Browser Compatibility Testing
Keep in mind that, even if CSS validation is done correctly, there is still a high probability that different browsers may interpret style differently. That’s why it is considered an excellent validation technique to perform cross-browser compatibility testing.
For this purpose, there are numerous specialized tools that can be utilized. The ones we recommend include: Browserstack, Lambda Test, and more.
So, these are a few proven techniques for effectively validating CSS and JavaScript codes. Now, let’s move on to the tools section that will help you automate this process.
Useful Tools for Performing JavaScript and CSS Validation
Below we have discussed some of the useful tools that web developers can utilize to easily perform JavaScript and CSS validation.
1. JavaScript Validator by Minifier
Minifier is a comprehensive toolkit offering a wide range of tools for developers. One of them includes a JavaScript validator. It is completely free to use and trained on all the modern validation rules and regulations to ensure maximum accuracy and efficiency.
The process is simple, just paste the JavaScript code in the input box, and hit the “Validate” button to initialize the process. If the code contains any sort of errors, it will be highlighted along with the line number and brief description.
Whereas, if the code is error-free, then this validator will display “Valid Code.” To demonstrate all this in a better way, we are attaching a screenshot below, check it out.
As can be seen, the tool has highlighted the bugs along with proper detail so that developers can easily identify and fix them.
The good thing is that this online tool doesn’t have any code length limit. So, there is no need to worry about the code length.
2. CSS Validator by Minifier
Minifier also offers a 100% free CSS validator as well. This will eliminate the need for developers to refer to different platforms or tools to get the job done because they are getting both on a single platform.
This CSS validator is based on CSS validation standards. This allows it to make sure that the entered code is error-free and follows the right syntax. If yes, then you will receive the output “Valid Code.”
On the other hand, if there are any sort of errors, then the tool will highlight them for quick and easy fixing. Take a look at the attachment below.
The notable thing about this tool is that it also provides a brief description of the highlighted error.
Wrapping Up
Validating both your JavaScript and CSS code is crucial to ensure the site is working fine and providing a good experience to the visitors. Apart from this, validating also helps prevent security vulnerabilities on the websites. There are numerous techniques and tools available that developers can consider adopting in this regard. In this blog post, we have discussed both in complete detail, hopefully, you will find them valuable.
