How to add a CSS class to an element on click - React
Question
How do you add a CSS class to an existing REACT element on click?
I have a JSFiddle created: https://jsfiddle.net/5r25psub/
In the fiddle, the code only works if I have the statement: this.setState({color:blue});
I want something like this.setState({className: 'green'}); What am I doing wrong?
Code:
<html>
<script>
var Hello = React.createClass({
getInitialState: function(){
return {
color: 'blue'
};
},
handleClick: function(){
if (this.state.color === 'blue'){
this.setState({className = " green"});
} else {
this.setState({color: 'blue'});
}
},
render: function() {
return <button className={this.state.className} onClick={this.handleClick}>My background is: {this.state.color}, Click me to change</button>;
}
});
React.render(<Hello name="World" />, document.getElementById('container'));
</script>
<body>
<script src="https://facebook.github.io/react/js/jsfiddle-integration.js"></script>
<style>
.green {
background-color: lightgreen;
}
.blue {
background-color: lightblue;
}
</style>
<div id="container">
<!-- This element's contents will be replaced with your component. -->
</div>
</body>
</html>
4 answers
solution1
4 2016-03-30 19:43:49
You can use the module classnames found here:
https://www.npmjs.com/package/classnames
So you would do something like:
getClassNames() {
return classNames({
'blue': this.state.clicked,
'green': !this.state.clicked
});
},
render () {
return <button className={this.getClassNames()} onClick={this.setState({clicked: !this.state.clicked})>
}
solution2
1 2016-03-30 19:31:31
You need to add all state parameters to getInitialState , right now the only thing you have is color , so this.state.color is the only thing in there
When you set your state to className: something, that is the only thing in there now, even color is gone...and that is why the initial color is the normal bland gray
you have a syntax error in setState as well, its not
this.setState({className = " green"});
It should be:
this.setState({className: " green"});
Finally, React.render is deprecated, you need to use ReactDOM.render now
solution3
0 2016-03-30 19:44:11
https://jsfiddle.net/ajvf50s6/3/
Most probably, you should better do a verification based on the className , not on the color state property:
handleClick: function(){
if (this.state.className === 'blue'){
this.setState({className: "green"});
} else {
this.setState({className: "blue"});
}
}
Also, as @Omarjmh mentioned, you have a typo in your code. {className = " green"} is wrong assignment.
solution4
0 2018-09-14 06:49:32
Rather than using two state variables, you can do like this.
Since the initial state of color is blue, you can change the handleClick function as :
handleClick: function(){
if (this.state.color === 'blue'){
this.setState({color : "green"});
} else {
this.setState({color: 'blue'});
}
}
And, for the className, consider a variable :
let colorClass= this.state.color === "blue" ? "blue" : "green"
Now, replace the className as below and you need to enclose that object where you call div class.
return <button className={colorClass} onClick={this.handleClick}>My background is: {this.state.color}, Click me to change</button>;
I hope it works fine.
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.