Q:

React: input type="checkbox" onChange not triggered

Can anyone tell me why handleChange isn't triggered when I click any of the checkboxes?  The checkboxes is rendered as I want with the expected value, but the click handler is not triggered. 
 37   var AutocompleteFromCheckboxes = React.createClass({
 38     handleChange: function(e) {
 39       console.log('hi');
 40       return 1;
 41     },
 42     render: function() {
 43       var autocompleteFrom = this.props.autocomplete_from.map(function(value) {
 44         return (
 45           <label for={value}>
 46             <input type="checkbox" name={value} value="{value}"
 47               onChange={this.handleChange}
 48               ref="autocomplete-from"/>
 49             {value}
 50           </label>
 51         );
 52       });
 53       return (
 54         <div className="autocomplete-from">
 55           {autocompleteFrom}
 56         </div>
 57       );
 58     }
 59   });

A:

In your code the anonymous function runs with the wrong context: as soon as you don't set it explicitly it's being set to undefined. 
It means that this is undefined hence this.handleChange should throw an exception (not sure why you haven't checked the console for that.  And if you had - why you didn't mention it). 
To solve the problem you may pass the context explicitly as the second argument for the Array.prototype.map function call:
var autocompleteFrom = this.props.autocomplete_from.map(function(value) {
    // ...
}, this);

And as soon as you solve this particular issue and ready to dive into the details on how this works in JS, please follow this amazing answer.