[Solved]-ReactJS passing object instead of function inside onClick-Reactjs

var TodoList = React.createClass({
    markComplete: function() {
        console.log("geelo");
        alert("ANYTHING");
    },

render: function(){ 
        var createItem = function(itemText, index){
            return (
                <li key={index + itemText}>
                    {itemText}<span id="markComplete" onClick={this.markComplete}>X</span>
                </li>
            );
        };
        return <ul id="list-container">{this.props.items.map(createItem.bind(this))}</ul>
    }
});