First of all, you can’t pass to alert second argument, use concatenation instead
alert("Input is " + inputValue);
Example
However in order to get values from input better to use states like this
var MyComponent = React.createClass({
getInitialState: function () {
return { input: '' };
},
handleChange: function(e) {
this.setState({ input: e.target.value });
},
handleClick: function() {
console.log(this.state.input);
},
render: function() {
return (
<div>
<input type="text" onChange={ this.handleChange } />
<input
type="button"
value="Alert the text input"
onClick={this.handleClick}
/>
</div>
);
}
});
ReactDOM.render(
<MyComponent />,
document.getElementById('container')
);
<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="container"></div>