Validate TextBox on Button Click using JavaScript

In this article, we'll explore how to perform client-side validation for a TextBox using JavaScript when a button is clicked.

Method 1: Using Basic JavaScript Validation #

To start, let's delve into the basic approach of validating a TextBox using JavaScript.

This method involves using simple if-else conditions to check whether the TextBox input is valid or not.

Explanation:

1. An input TextBox element and a button are created in the HTML.
2. The validate function is triggered when the button is clicked.
3. Inside the function, the value of the TextBox is retrieved using getElementById() method.
4. An if-else condition checks if the TextBox is empty or not.

Method 2: Using Regular Expressions #

An advanced method employs regular expressions for more precise validation. Regular expressions provide powerful pattern matching capabilities.

Explanation:

1. Similar to Method 1, an input TextBox and a button are created.
2. The validate function obtains the TextBox value.
3. A regular expression pattern is defined to allow only alphabetic characters.
4. The test method of the pattern checks if the input matches the pattern.
5. Alerts are displayed based on whether the input passes the validation or not.

Conclusion: #

In this article, you learned two methods to validate a TextBox using JavaScript when a button is clicked.

The first method involves basic if-else conditions to check for empty input, while the second method employs regular expressions for more specific validation criteria.