[javascript] React - Preventing Form Submission

I've been experimenting with React. In my experiement, I'm using the Reactstrap framework.When I click a button, I've noticed that the HTML form submits. Is there a way to prevent form submission when a button is clicked?

I've recreated my issue here. My form is pretty basic and looks like this:

<Form>
  <h3>Buttons</h3> 
  <p>
    <Button color="primary" onClick={this.onTestClick}>primary</Button>&nbsp;
  </p>
</Form>

What am I missing?

import React, { Component } from 'react';

export class Form extends Component {
  constructor(props) {
    super();
    this.state = {
      username: '',
    };
  }
  handleUsername = (event) => {
    this.setState({
      username: event.target.value,
    });
  };

  submited = (event) => {
    alert(`Username: ${this.state.username},`);
    event.preventDefault();
  };
  render() {
    return (
      <div>
        <form onSubmit={this.submited}>
          <label>Username:</label>
          <input
            type="text"
            value={this.state.username}
            onChange={this.handleUsername}
          />
          <button>Submit</button>
        </form>
      </div>
    );
  }
}

export default Form;

componentDidUpdate(){               
    $(".wpcf7-submit").click( function(event) {
        event.preventDefault();
    })
}

You can use componentDidUpdate and event.preventDefault() to disable form submission.As react does not support return false.

You have prevent the default action of the event and return false from the function.

function onTestClick(e) {
    e.preventDefault();
    return false;
}

No JS needed really ... Just add a type attribute to the button with a value of button

<Button type="button" color="primary" onClick={this.onTestClick}>primary</Button>&nbsp;

By default, button elements are of the type "submit" which causes them to submit their enclosing form element (if any). Changing the type to "button" prevents that.

There's another, more accessible solution: Don't put the action on your buttons. There's a lot of functionality built into forms already. Instead of handling button presses, handle form submissions and resets. Simply add onSubmit={handleSubmit} and onReset={handleReset} to your form elements.

To stop the actual submission just include event in your function and an event.preventDefault(); to stop the default submission behavior. Now your form behaves correctly from an accessibility standpoint and you're handling any form of submission the user might take.

In your onTestClick function, pass in the event argument and call preventDefault() on it.

function onTestClick(e) {
    e.preventDefault();
}

2 ways

First one we pass the event in the argument right into the onClick.

  onTestClick(e) {
    e.preventDefault();
    alert('here');
  }

  // Look here we pass the args in the onClick
  <Button color="primary" onClick={e => this.onTestClick(e)}>primary</Button>&nbsp;

Second one we pass it into argument and we did right in the onClick

  onTestClick() {
    alert('here');
  }

  // Here we did right inside the onClick, but this is the best way
  <Button color="primary" onClick={e => (e.preventDefault(), this.onTestClick())}>primary</Button>&nbsp;

Hope that can help

preventDefault is what you're looking for. To just block the button from submitting

<Button onClick={this.onClickButton} ...

code

onClickButton (event) {
  event.preventDefault();
}

If you have a form which you want to handle in a custom way you can capture a higher level event onSubmit which will also stop that button from submitting.

<form onSubmit={this.onSubmit}>

and above in code

onSubmit (event) {
  event.preventDefault();

  // custom form handling here
}

function onTestClick(evt) {
  evt.stopPropagation();
}

Make sure you put the onSubmit attribute on the form not the button in case you have a from.

<form onSubmit={e => e.preventDefault()}>
    <button onClick={this.handleClick}>Click Me</button>
</form>

Make sure to change the button onClick attribute to your custom function.