How to get value of textbox in React?

Question

I just started using React.js, and I'm just not sure whether there is a special way to get the value of a textbox, returned in a component like this:

var LoginUsername = React.createClass({   render: function () {     return (       <input type="text" autofocus="autofocus" onChange={this.handleChange} />     )   },   handleChange: function (evt) {     this.setState({ value: evt.target.value.substr(0, 100) });   } }); 

Answer 1

As described in documentation You need to use controlled input. To make an input - controlled you need to specify two props on it

1. onChange - function that would set component state to an input value every time input is changed
2. value - input value from the component state (this.state.value in example)

Example:

  getInitialState: function() {     return {value: 'Hello!'};   },   handleChange: function(event) {     this.setState({value: event.target.value});   },   render: function() {     return (       <input         type="text"         value={this.state.value}         onChange={this.handleChange}       />     );   } 

More specifically about textarea - here

Answer 2

just update your input to the value

var LoginUsername = React.createClass({   getInitialState:function(){      return {         textVal:''      }  },   render: function () {     return (       <input type="text" value={this.state.textVal} autofocus="autofocus" onChange={this.handleChange} />     )   },   handleChange: function (evt) {     this.setState({ textVal: evt.target.value.substr(0, 100) });   } }); 

Your text input value is always in the state and you can get the same by this.state.textVal