Generate svg graphs json data...
This script uses <a href="http://jerrywham.github.io/phpGraph/">phpGraph.php</a> from my friend <a href="https://www.ecyseo.net/article29/phpgraph-afficher-des-graphiques-svg-grace-a-php">JerryWham</a> 
<li>data: array of data (sequential or associative)</li>
<li>w,h: width and height (opt.)</li>
<li>color: graph's color in FFFFFF format only (opt.)</li>
<li>lines: set type of graph to line (default type is bars)</li>
<li>filled: set type of graph to filled area (default type is bars)</li>
<li>steps: the steps in the ordinate (by default, it will be calculated)</li>
<li>title: the graphic's title (opt.)</li>

<li>help: displays this text</li>
<li>version: displays this api's version</li>
<li>download: downloads the API zip</li>