I'm using react and I want to get the value of the selected option of a dropdown in react but I don't know how. Any suggestions? thanks!
My dropdown is just a select like:
<select id = "dropdown">
<option value="N/A">N/A</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
</select>
The code in the render method represents the component at any given time.
If you do something like this, the user won't be able to make selections using the form control:
<select value="Radish">
<option value="Orange">Orange</option>
<option value="Radish">Radish</option>
<option value="Cherry">Cherry</option>
</select>
So there are two solutions for working with forms controls:
Controlled Components Use component state to reflect the user's selections. This provides the most control, since any changes you make to state will be reflected in the component's rendering:
example:
var FruitSelector = React.createClass({
getInitialState:function(){
return {selectValue:'Radish'};
},
handleChange:function(e){
this.setState({selectValue:e.target.value});
},
render: function() {
var message='You selected '+this.state.selectValue;
return (
<div>
<select
value={this.state.selectValue}
onChange={this.handleChange}
>
<option value="Orange">Orange</option>
<option value="Radish">Radish</option>
<option value="Cherry">Cherry</option>
</select>
<p>{message}</p>
</div>
);
}
});
React.render(<FruitSelector name="World" />, document.body);
JSFiddle: http://jsfiddle.net/xe5ypghv/
Uncontrolled Components The other option is to not control the value and simply respond to onChange events. In this case you can use the defaultValue prop to set an initial value.
<div>
<select defaultValue={this.state.selectValue}
onChange={this.handleChange}
>
<option value="Orange">Orange</option>
<option value="Radish">Radish</option>
<option value="Cherry">Cherry</option>
</select>
<p>{message}</p>
</div>
http://jsfiddle.net/kb3gN/10396/
The docs for this are great: http://facebook.github.io/react/docs/forms.html
and also show how to work with multiple selections.
UPDATE
A variant of Option 1 (using a controlled component) is to use Redux and React-Redux to create a container component. This involves connect and a mapStateToProps function, which is easier than it sounds but probably overkill if you're just starting out.
Implement your Dropdown as
<select id = "dropdown" ref = {(input)=> this.menu = input}>
<option value="N/A">N/A</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
</select>
Now, to obtain the selected option value of the dropdown menu just use:
let res = this.menu.value;
It should be like:
import React, { useState } from "react";
export default function App() {
const getInitialState = () => {
const value = "Orange";
return value;
};
const [value, setValue] = useState(getInitialState);
const handleChange = (e) => {
setValue(e.target.value);
};
return (
<div>
<select value={value} onChange={handleChange}>
<option value="Orange">Orange</option>
<option value="Radish">Radish</option>
<option value="Cherry">Cherry</option>
</select>
<p>{`You selected ${value}`}</p>
</div>
);
}
you can see it here: https://codesandbox.io/s/quizzical-https-t1ovo?file=/src/App.js:0-572
Just use onChange event of the <select> object.
Selected value is in e.target.value then.
By the way, it's a bad practice to use id="...". It's better to use ref=">.."
http://facebook.github.io/react/docs/more-about-refs.html
As for front-end developer many time we are dealing with the forms in which we have to handle the dropdowns and we have to
use the value of selected dropdown to perform some action or the send the value on the Server, it's very simple
you have to write the simple dropdown in HTML just put the one onChange method for the selection in the dropdown
whenever user change the value of dropdown set that value to state so you can easily access it in AvFeaturedPlayList
1
remember you will always get the result as option value and not the dropdown text which is displayed on the screen
import React, { Component } from "react";
import { Server } from "net";
class InlineStyle extends Component {
constructor(props) {
super(props);
this.state = {
selectValue: ""
};
this.handleDropdownChange = this.handleDropdownChange.bind(this);
}
handleDropdownChange(e) {
this.setState({ selectValue: e.target.value });
}
render() {
return (
<div>
<div>
<div>
<select id="dropdown" onChange={this.handleDropdownChange}>
<option value="N/A">N/A</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
</select>
</div>
<div>Selected value is : {this.state.selectValue}</div>
</div>
</div>
);
}
}
export default InlineStyle;
Using React Functional Components:
const [option,setOption] = useState()
function handleChange(event){
setOption(event.target.value)
}
<select name='option' onChange={handleChange}>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
</select>
import React from 'react';
import Select from 'react-select';
const options = [
{ value: 'chocolate', label: 'Chocolate' },
{ value: 'strawberry', label: 'Strawberry' },
{ value: 'vanilla', label: 'Vanilla' },
];
class App extends React.Component {
state = {
selectedOption: null,
};
handleChange = selectedOption => {
this.setState({ selectedOption });
console.log(`Option selected:`, selectedOption);
};
render() {
const { selectedOption } = this.state;
return (
<Select
value={selectedOption}
onChange={this.handleChange}
options={options}
/>
);
}
}
And you can check it out on this site.
It is as simple as that. You just need to use "value" attributes instead of "defaultValue" or you can keep both if a pre-selected feature is there.
....
const [currentValue, setCurrentValue] = useState(2);
<select id = "dropdown" value={currentValue} defaultValue={currentValue}>
<option value="N/A">N/A</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
</select>
.....
setTimeut(()=> {
setCurrentValue(4);
}, 4000);
In this case, after 4 secs the dropdown will be auto-selected with option 4.
I was making a drop-down menu for a language selector - but I needed the dropdown menu to display the current language upon page load. I would either be getting my initial language from a URL param example.com?user_language=fr, or detecting it from the user’s browser settings. Then when the user interacted with the dropdown, the selected language would be updated and the language selector dropdown would display the currently selected language.
In the spirit of the other answers using food examples, I got all sorts of fruit goodness for you.
First up, answering the initially asked question with a basic React functional component - two examples with and without props, then how to import the component elsewhere.
Next up, the same example - but juiced up with Typescript.
Then a bonus finale - A language selector dropdown component using Typescript.
Basic React (16.13.1) Functional Component Example. Two examples of FruitSelectDropdown , one without props & one with accepting props fruitDetector
import React, { useState } from 'react'
export const FruitSelectDropdown = () => {
const [currentFruit, setCurrentFruit] = useState('oranges')
const changeFruit = (newFruit) => {
setCurrentFruit(newFruit)
}
return (
<form>
<select
onChange={(event) => changeFruit(event.target.value)}
value={currentFruit}
>
<option value="apples">Red Apples</option>
<option value="oranges">Outrageous Oranges</option>
<option value="tomatoes">Technically a Fruit Tomatoes</option>
<option value="bananas">Bodacious Bananas</option>
</select>
</form>
)
}
Or you can have FruitSelectDropdown accept props, maybe you have a function that outputs a string, you can pass it through using the fruitDetector prop
import React, { useState } from 'react'
export const FruitSelectDropdown = ({ fruitDetector }) => {
const [currentFruit, setCurrentFruit] = useState(fruitDetector)
const changeFruit = (newFruit) => {
setCurrentFruit(newFruit)
}
return (
<form>
<select
onChange={(event) => changeFruit(event.target.value)}
value={currentFruit}
>
<option value="apples">Red Apples</option>
<option value="oranges">Outrageous Oranges</option>
<option value="tomatoes">Technically a Fruit Tomatoes</option>
<option value="bananas">Bodacious Bananas</option>
</select>
</form>
)
}
Then import the FruitSelectDropdown elsewhere in your app
import React from 'react'
import { FruitSelectDropdown } from '../path/to/FruitSelectDropdown'
const App = () => {
return (
<div className="page-container">
<h1 className="header">A webpage about fruit</h1>
<div className="section-container">
<h2>Pick your favorite fruit</h2>
<FruitSelectDropdown fruitDetector='bananas' />
</div>
</div>
)
}
export default App
FruitSelectDropdown with Typescript
import React, { FC, useState } from 'react'
type FruitProps = {
fruitDetector: string;
}
export const FruitSelectDropdown: FC<FruitProps> = ({ fruitDetector }) => {
const [currentFruit, setCurrentFruit] = useState(fruitDetector)
const changeFruit = (newFruit: string): void => {
setCurrentFruit(newFruit)
}
return (
<form>
<select
onChange={(event) => changeFruit(event.target.value)}
value={currentFruit}
>
<option value="apples">Red Apples</option>
<option value="oranges">Outrageous Oranges</option>
<option value="tomatoes">Technically a Fruit Tomatoes</option>
<option value="bananas">Bodacious Bananas</option>
</select>
</form>
)
}
Then import the FruitSelectDropdown elsewhere in your app
import React, { FC } from 'react'
import { FruitSelectDropdown } from '../path/to/FruitSelectDropdown'
const App: FC = () => {
return (
<div className="page-container">
<h1 className="header">A webpage about fruit</h1>
<div className="section-container">
<h2>Pick your favorite fruit</h2>
<FruitSelectDropdown fruitDetector='bananas' />
</div>
</div>
)
}
export default App
Bonus Round: Translation Dropdown with selected current value:
import React, { FC, useState } from 'react'
import { useTranslation } from 'react-i18next'
export const LanguageSelectDropdown: FC = () => {
const { i18n } = useTranslation()
const i18nLanguage = i18n.language
const [currentI18nLanguage, setCurrentI18nLanguage] = useState(i18nLanguage)
const changeLanguage = (language: string): void => {
i18n.changeLanguage(language)
setCurrentI18nLanguage(language)
}
return (
<form>
<select
onChange={(event) => changeLanguage(event.target.value)}
value={currentI18nLanguage}
>
<option value="en">English</option>
<option value="de">Deutsch</option>
<option value="es">Español</option>
<option value="fr">Français</option>
</select>
</form>
)
}
An invaluable resource for React/Typescript
You can handle it all within the same function as following
<select className="form-control mb-3" onChange={(e) => this.setState({productPrice: e.target.value})}>
<option value="5">5 dollars</option>
<option value="10">10 dollars</option>
</select>
as you can see when the user select one option it will set a state and get the value of the selected event without furder coding require!
If you want to get value from a mapped select input then you can refer to this example:
class App extends React.Component {
constructor(props) {
super(props);
this.state = {
fruit: "banana",
};
this.handleChange = this.handleChange.bind(this);
}
handleChange(e) {
console.log("Fruit Selected!!");
this.setState({ fruit: e.target.value });
}
render() {
return (
<div id="App">
<div className="select-container">
<select value={this.state.fruit} onChange={this.handleChange}>
{options.map((option) => (
<option value={option.value}>{option.label}</option>
))}
</select>
</div>
</div>
);
}
}
export default App;
import {React, useState }from "react";
function DropDown() {
const [dropValue, setDropValue ]= useState();
return <>
<div>
<div class="dropdown">
<button class="btn btn-secondary" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false">
{dropValue==null || dropValue=='' ?'Select Id':dropValue}
</button>
<ul class="dropdown-menu" aria-labelledby="dropdownMenuButton1">
<li><a class="dropdown-item" onClick={()=> setDropValue('Action')} href="#">Action</a></li>
<li><a class="dropdown-item" onClick={()=> setDropValue('Another action')} href="#">Another action</a></li>
<li><a class="dropdown-item" onClick={()=> setDropValue('Something else here')} href="#">Something else here</a></li>
</ul>
</div>
</div>
</>
}
export default DropDown
<select value ={this.state.value} onChange={this.handleDropdownChange}>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
</select>
As mentioned by Karen above you can just use the target value from the event triggered. Here is a small snippet of the code
`<select class="form-select py-2"
onChange={(e) => setVotersPerPage(e.target.value)}>
<option value="10">10</option>
<option value="25">25</option>
<option value="50">50</option>
</select>`
I want to convert javascript code to Reactjs. How i write this kind of code in React.js. Help me to explain how i do this in react.js. I also mention my react code, where I did wrong in the code and what can in do to run my code properly.
const select = document.querySelector('select');
const html = document.querySelector('html');
document.body.style.padding = '10px';
function update(bgColor, textColor) {
html.style.backgroundColor = bgColor;
html.style.color = textColor;
}
select.onchange = function() {
( select.value === 'black' ) ? update('black','white') : update('white','black');
}
<--Html--> This is Html Code which i want to convert it all in jsx file i React.js
<html>
<body>
<label for="theme">Select theme: </label>
<select id="theme">
<option value="white">White</option>
<option value="black">Black</option>
</select>
<h1>This is my website</h1>
</body>
</html>
<-- React.js-->
where I did wrong in the code and what can in do to run my code properly.
import React from 'react';
import './App.css';
class App extends React.Component{
constructor(){
super();
this.state={
whether:'',
color:''
}
}
change=(event)=>{
this.setState({whether: event.target.value});
}
handleChange=(event)=>{
this.setState({color: event.target.value});
}
render(){
let pop=this.state.color;
return(
<div>
<label for="weather">Select the weather type today: </label>
<select id="weather" onChange={this.change} >
<option value="">--Make a choice--</option>
<option value="Its sunny Today">Sunny</option>
<option value="ITS Rainy Today">Rainy</option>
<option value="snowing">Snowing</option>
<option value="overcast">Overcast</option>
</select>
<label for="theme">Select theme: </label>
<select id="theme" onChange={this.handleChange} >
<option value="white">White</option>
<option value="black">Black</option>
</select>
<h1 style={{backgroundColor:{this.state.color}}} >{this.state.whether}</h1>
</div>
)
}
}
export default App;
You should fix style in h1 tag
<h1 style={{backgroundColor:`${this.state.color}`}} >{this.state.whether}</h1>
I have a problem with select in JavaScript. I'd like to change option of select. The option is changing, but text is default. Why is that? What can I change in my code? I need timeout, because script is loading slowly.
setTimeout(() => {
if(this.props.Locale === "en-EN") {
let country = document.getElementById("Country");
country.getElementsByTagName("option")[10].selected = "selected";
}
}, 3000);
You can control the selected option using the value property of the select component. You can bind it to an item in state and then set that to whatever you need. I've given an example below, which isn't particularly great code, but gives a demonstration of how this might work:
class App extends React.Component {
state = {
selectedOption: 2,
}
updateSelectedOption(newValue) {
this.setState({
selectedOption: newValue
});
}
render() {
return (
<div>
<select
onChange={({ target }) => { this.updateSelectedOption(target.value) }}
value={this.state.selectedOption}
>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
</select>
<button onClick={() => this.updateSelectedOption(1)}>1</button>
<button onClick={() => this.updateSelectedOption(5)}>5</button>
</div>
)
}
}
ReactDOM.render(
<App />,
document.getElementById('app')
)
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="app"></div>
I need to change the contents of dropdown Method&Minorhead based on the selection in dropdown MajorHead using React.
If I select cheating in majorhead, then it's supposed to show a&b in minorHead and apple, orange in Method.
If I select abduction in majorhead, then it's supposed to show AB&BC in minorhead and cat, dog in Method...
import React, { Component } from 'react';
class Profile extends Component {
render() {
return (
<form>
<div className="form-group">
<label for="inputState">Major head</label>
<select id="inputState" className="form-control"/>
<option selected>Choose...</option>
<option>Cheating</option>
<option>Abduction</option>
<option>House brake</option>
</div>
<div className="form-group">
<label for="inputState">Minor head</label>
<select id="inputState" className="form-control"/>
<option selected>Choose...</option>
<option>a</option>
<option>b</option>
<option>AB</option>
<option>BC</option>
<option>X</option>
<option>Y</option>
</div>
<div className="form-group">
<label for="inputState">method</label>
<select id="inputState" className="form-control"/>
<option selected>Choose...</option>
<option>apple</option>
<option>orange</option>
<option>cat</option>
<option>dog</option>
</div>
</form>
)
}
}
export default Profile;
For each option in your major head Select, i would create an array of supported values for method and minor.
class App extends React.Component {
constructor(props) {
super(props)
this.state = {
selectedView: 'Cheating'
}
}
render() {
const { selectedView } = this.state
const VIEWS = [
{
name: 'Cheating',
minor: ['a', 'b'],
method: ['apple', 'orange']
}, {
name: 'Abductions',
minor: ['AB', 'BC', 'X'],
method: ['cat', 'dog']
}
]
const getMajorMethod = () => {
const view = VIEWS.filter(({name}) => name === selectedView)[0]
return (
<div>
<select>
{view.minor.map(m => <option>{m}</option>)}
</select>
<select>
{view.method.map(m => <option>{m}</option>)}
</select>
</div>
)
}
return (
<div>
<select onChange={(e) => this.setState({selectedView: e.target.value})}>
{VIEWS.map(({name}) => <option value={name}>{name}</option>)}
</select>
{getMajorMethod()}
</div>
)
}
}
ReactDOM.render(<App />, document.getElementById('app'))
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="app"></div>
A structure like this will allow you to (within your initial MAJOR select) map over your VIEWS and apply the name prop to the options.
You can then have another map that shows two other selects (minor & method) with the VIEWS relative minor and method arrays being their options
I have a form in which I am using html select element.
<select className="form-control" id="ntype" required >
<option value = "">None</option>
<option value = "1">1</option>
<option value = "2">2</option>
<option value = "3">3</option>
</select>
I know with html input type element we can attach ref like below code
ref = {(input) => { this.nHeading = input; }}
and
<input
type = "text"
className = "form-control"
id = "tInput"
placeholder = "Sample input"
ref = {(input) => { this.sInput = input; }}
required
/>
How can I attach ref to <Select> element and get selected option value from the attached ref when form is submitted?
Do I need to attach ref to each options or select element itself?
You can store the value in a state on change and later use that i.e make it a controlled component
class App extends React.Component {
constructor() {
super();
this.state = {selectValue: ''}
}
callThis = (e) => {
this.setState({selectValue: e.target.value}, ()=> {console.log(this.state.selectValue)});
}
render() {
return (
<select onChange={this.callThis}className="form-control" id="ntype" required >
<option value = "">None</option>
<option value = "1">1</option>
<option value = "2">2</option>
<option value = "3">3</option>
</select>
)
}
}
ReactDOM.render(<App/>, document.getElementById('app'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="app"></div>
Or you can use refs to get the value like this
class App extends React.Component {
constructor() {
super();
this.state = {selectValue: ''}
}
callThis = (e) => {
console.log(this.selectVal.value)
}
render() {
return (
<div><select ref={(input) => this.selectVal = input} className="form-control" id="ntype" required >
<option value = "">None</option>
<option value = "1">1</option>
<option value = "2">2</option>
<option value = "3">3</option>
</select>
<input type="button" value="click" onClick={this.callThis}/></div>
)
}
}
ReactDOM.render(<App/>, document.getElementById('app'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="app"></div>
I would give each element a value and onChange handler for the select element like this
<select className="form-control"onChange={this.onChange.bind(this)}>
<option value="">None</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
And define an onChange handler that sets the state of the selection
onChange(e){
this.setState({value: e.target.value}, function(){
// do other stuff
});
}
If you are using React functional components, you can do the following.
import { useState, useRef } from 'react';
...
const selectRef = useRef(null)
<select className="form-control" id="ntype" required ref={selectRef}>
<option value = "">None</option>
<option value = "1">1</option>
<option value = "2">2</option>
<option value = "3">3</option>
</select>
then you can access the value in your submit logic by,
selectRef.current.value
You can just use an onChange function to set the value of the Ref. E.g.:
<select className="form-control" id="ntype" required onChange={e => {yourRef.current = e.target.value}} >
<option value = "">None</option>
<option value = "1">1</option>
<option value = "2">2</option>
<option value = "3">3</option>
</select>