I've run elasticsearch.bat and queried this in browser with localhost:9200. JSON object returned as follows, so all ok so far.

```
 {
  "status" : 200,
  "name" : "hwils_01_dev",
  "cluster_name" : "elasticsearch_hwils_dev",
  "version" : {
    "number" : "1.7.2",
    "build_hash" : "e43676b1385b8125d647f593f7202acbd816e8ec",
    "build_timestamp" : "2015-09-14T09:49:53Z",
    "build_snapshot" : false,
    "lucene_version" : "4.10.4"
  },
  "tagline" : "You Know, for Search"
}   

```

I've downloaded and linked via tag to my index.html the elasticsearch.js

```
<script src="elasticsearch-js/elasticsearch.js"></script>

```

(incidentally there's more than 1 .js in the download - do I need to link them all?)

I've then run added to another tag the code

```
var client = new elasticsearch.Client({
    host: 'localhost:9200',
    log: 'trace'
});

```

and output this to console - JSON object returned so again, presumably all ok up to this point.

If I then run

```
client.ping({
    requestTimeout: 30000,

    // undocumented params are appended to the query string
    hello: 'elasticsearch'
    }, function (error) {
    if (error) {
        console.error('elasticsearch cluster is down!');
    } else {
        console.log('All is well');
    }
});

```

I get the error message returned. And I don't know why.

Incidentally

```
var elasticsearch = require('elasticsearch');

```

returns "Uncaught reference error: require is not defined" which would suggest I'm missing at least one other .js file with that function?