onClick无法正常工作？

Question

我似乎在试图听一个事件时做错了什么。我已在输入框中发出警报，但即使这样似乎也无法正常工作。可能是什么原因？

import React from 'react';

class PersonalDetails extends React.Component {

    constructor(props) {
        super(props);
        console.log('PersonalDetails constructor......');
        console.log(props);
        this._handleTextChange = this._handleTextChange.bind(this);
        this._handleSave = this._handleSave.bind(this);

    }

    _handleTextChange(event) {

        this.props.onChange(event);
    }

    _handleSave(event) {
        this.props.onSave(event);
    }

    render() {
        return (

            <div >
                <h2 className="title" >Your Contact Details </h2>
                <h2> Your name </h2>

                <label for="Firstname">First Name: </label>
                <input  name="firstname"
                    value={this.props.firstname}
                    type="text"
                    onChange={this._handleTextChange}>
                </input>

                <input
                    type="image"
                    alt="Confirm"
                    name="confirm"
                    src="/myaccount/btnConfirm.gif"
                    //onClick={this._handleSave}/>
                    onClick={function(){alert("Hello World!")}}/>
                <br/>
                <br/>
                <div className="line"></div>


            </div>
        );
    }
}


export default PersonalDetails;