Updating Dygraph with ajax - ajax

Question

I have below code which pull data from mysql using ajax json and draw Dygraph chart which it works fine but when my problem is updating the chart.
When I try to update the graph I am getting this error:
Uncaught ReferenceError: g is not defined
which is already defined
all these code are in document ready fucntion
// get data from server
$.ajax({
type: 'POST',
url: 'php/proccess.php',
data: {
type: "jobgraph",
job: job
},
dataType: "json",
success: function(response) {
//console.log(response);
var i = 0;
$.each(response, function(key, value) {
test[i] = [new Date(value[0]), value[1] / 1000, value[2]];
i++;
});
if (test) {
document.addEventListener("mousewheel", function() {
lastClickedGraph = null;
}, false);
document.addEventListener("click", function() {
lastClickedGraph = null;
}, false);
if (response) {
var g = new Dygraph(document.getElementById("noroll"),
test, {
labels: ["Date", "Voltage", "Temp"],
digitsAfterDecimal: 3,
interactionModel: {
'mousedown': downV3,
'mousemove': moveV3,
'mouseup': upV3,
'click': clickV3,
'dblclick': referesh,
'mousewheel': scrollV3
}
}
);
}
}
},
error: function(jqXHR, textStatus, errorThrown) {
if (jqXHR.status == 500) {
alert('Internal error: ' + jqXHR.responseText);
} else {
console.log(errorThrown);
}
},
});
// update Data every 2 second by pulling new data from mysql server
window.intervalId = setInterval(function() {
$.ajax({
type: 'POST',
url: 'php/proccess.php',
data: {
type: "jobgraph",
job: job
},
dataType: "json",
success: function(response) {
//console.log(response);
var i = 0;
$.each(response, function(key, value) {
test[i] = [new Date(value[0]), value[1] / 1000, value[2]];
i++;
});
//console.log(test);
g.updateOptions({
'file': test
});
},
error: function(jqXHR, textStatus, errorThrown) {
if (jqXHR.status == 500) {
alert('Internal error: ' + jqXHR.responseText);
} else {
console.log(errorThrown);
}
},
});
}, 2000); </pre>
//end update

Answer 1

In your setup, you define the graph with:
var g = new Dygraph(...
var limits the scope of g, so it's not accessible in your later call. Make the g variable available globally, or in a variable that you pass between functions.