Are you just looking for a simple line chart?
Personally, I would create PHP file that pulled the current price and then log the time and price to a database . I'd set a cron job so that it runs once every minute. So you'd have a sql table that looked something like this:
-------------------------
price | time
====================
285.24 | 8:57
285.88 | 8:56
283.65 | 8:55
284.01 | 8:54
From there just query your database and do a loop for each price instance that is in your database. Output your loops into the Labels and Data variables in the JS.
<script>
var sqlPrices=[<?php
while($info=mysqli_fetch_array($data))
echo $info['price'].',';
?>];
<?php
$data=mysqli_query($mysqli,"SELECT * FROM priceTable");
?>
var sqlLabels=[<?php
while($info=mysqli_fetch_array($data))
echo '"'.$info['time'].'",';
?>];
</script>
var data = {
labels: [sqlLabels],
datasets: [
{
label: "My First dataset",
fillColor: "rgba(220,220,220,0.2)",
strokeColor: "rgba(220,220,220,1)",
pointColor: "rgba(220,220,220,1)",
pointStrokeColor: "#fff",
pointHighlightFill: "#fff",
pointHighlightStroke: "rgba(220,220,220,1)",
data: [sqlPrices]
}
]
};
