Edit in JSFiddle

function geocode() {
    var location = document.getElementById("location").value;
    var resultDiv = document.getElementById("result");
    try {
        Gp.Services.geocode({
            location: location,
            apiKey: "calcul",
            onSuccess: function(result) {
                resultDiv.innerHTML = "<p>" + JSON.stringify(result) + "</p>"
                console.log(result);
            },
            onFailure: function(error) {
                resultDiv.innerHTML = "<p>" + error + "</p>"
            }
        });
    } catch (e) {
        resultDiv.innerHTML = "<p>" + e + "</p>"
    }
}

var infoDiv = document.getElementById("info");
infoDiv.innerHTML = "<p> Bibliothèque d'accès version " + Gp.servicesVersion + " (" + Gp.servicesDate + ")</p>";

<div id="params">
    <p>Localisant à géocoder :
        <input type="text" id="location" />
    </p>
</div>
<div id="go">
    <input type="button" value="Geocode" onclick="geocode()" />
</div>
<div id="result"></div>
<div id="info"></div>

#params {
    width: 100%;
    height: 50px;
    box-shadow: 0 0 10px #999;
    font-family: monospace;
    padding: 5px;
}

#go {
    padding: 5px;
    float: center;
    width: 100%;
    height: 30px;
}

#result {
    padding: 5px;
    width: 100%;
    height: 200px;
    box-shadow: 0 0 10px #999;
    font-family: monospace;
    overflow: scroll;
}
#info {
  padding: 5px;
  width: 100%;
  height: 20px;
  font-family: monospace;
}