Get data to NodeRed from Homepage (HighCharts)

I would like to extract the data from this chart using node-red:

http://fiskdata.se/raknare/live/live.php?locationId=109 The chart is labeled with "Preliminära resultat 2018" and I want the green and red series. I would like to have alerts and also trend the waterflow and temperature in my home automation.

In node red I am using a "http request node" -> "html node" -> "function" -> "Debug".

My Questions is: What selector should I use in "html node"? I have tried to solve it with web developer in firefox against the webpage but I do not understand it.

And what would my function look like to convert the two series into arrays in node red? Two series with value/date.

Image for Node_red Code

Solution

The following instructions will tell you how to find the url that gets the data behind a chart on a web page: https://onlinejournalismblog.com/2017/05/10/how-to-find-data-behind-chart-map-using-inspector/

Using those instructions, I think that for the page you have mentioned in your question it will be something like:

So in node-red you can then create a flow consisting of an inject node, a html in node using one of the above 2 URLs and one or more nodes that parse the output of the html in node.

kr Jan.