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In this tutorial, you will learn how to do input type url form validation in the reactjs application.
You can see the full code on Github
Other versions available:
We will create react application using the create-react-app tool to run the application.
npx create-react-app react-input-form
Now, let’s run the application
cd react-input-form
npm run start
It starts the application and opens localhost:3000
Input type url regular expression validation in reactjs
This example explains valid website URLs on change event handlers.
Here are steps for adding validation
- Create a component folder in src folder
- Lets create a Form a component named as
InputUrlComponent - Add form element inside a render function
- Create
<input>element withtype=urlinsideform - Create a button to handle submit functionality
- Attach
onChangebind event to input element - Create a two variables
websiteurlfor holding input url, isValid value to check validation succesful or not. - create a state object and initialize default values for
websiteurland isValid=false inside a constructor of a form component as seen belowconstructor(props) { super(props); this.state = { websiteUrl: "", isValid: false } } - form input
valueis bounded to the state values as seen below
<input type="text" name="websiteUrl" value={websiteUrl}
- we need to handle the user entered data on the input field, Otherwise, typed data is not shown, So added the
onChangeevent handler with the `changeUrl' function
onChange={this.changeUrl}
OnChange handler in reactbeing called while user typing the text. This will call changeUrl function defined as follows
changeUrl = e => {
const { value } = e.target;
const isValid = !value || this.validateWebsiteUrl(value);
this.setState({
websiteUrl: value,
isValid
});
};
This saves the entered url value and checks validation logic, stores the validation result as well as entered url.
- Let’s define the validation logic for url
validateWebsiteUrl = websiteUrl => {
const urlRegEx =
'[-a-zA-Z0-9@:%_+.~#?&//=]{2,256}(.[a-z]{2,4})?\b(/[-a-zA-Z0-9@:%_+.~#?&//=]*)?';
return urlRegEx.test(String(websiteUrl).toLowerCase());
};
Defined regular expression pattern for URL
This will check websiteUrl against regular expression using the test method
return true, if url is valid, else false
- Displayed error text in red color if isValid=false
- Disabled if entered URL is invalid
Complete code for handing input type form validation
import React, { Component } from "react";
class InputUrlComponent extends Component {
state = {
websiteUrl: "",
isValid: false
};
validateWebsiteUrl = websiteUrl => {
const urlRegEx =
'[-a-zA-Z0-9@:%_+.~#?&//=]{2,256}(.[a-z]{2,4})?\b(/[-a-zA-Z0-9@:%_+.~#?&//=]*)?';
return urlRegEx.test(String(websiteUrl).toLowerCase());
};
changeUrl = e => {
const { value } = e.target;
const isValid = !value || this.validateWebsiteUrl(value);
this.setState({
websiteUrl: value,
isValid
});
};
submitForm = () => {
const { websiteUrl } = this.state;
console.log("Website URL", websiteUrl);
};
render() {
const { isValid, websiteUrl } = this.state;
return (
<div className="App">
<form>
<input
type="text"
name="websiteUrl"
value={websiteUrl}
onChange={this.changeUrl}
/>
{!this.state.isValid && (
<div style={{ color: "red" }}>URL is invalid</div>
)}
<br></br>
<button onClick={this.submitForm} disabled={!isValid}>
Submit
</button>
</form>
</div>
);
}
}
export default InputUrlComponent;
InputUrlcomponent is called in App.js, here is the file.
import "./App.css";
import InputUrl from './components/Input-url';
function App() {
return (
<div className="App">
<h1>React Input type url pattern validation example</h1>
<InputUrl />
</div>
);
}
export default App;
Here is the output you have seen on the screen.
