title: How to draw multi line graph using phpGraphlib
body: <p>I have successfully created a line graph using phpGraphlib. But I don't get any idea how to draw a multiline graph using this library . The x-y values are stored in arrays here. My  code is here </p>
  
  <pre><code>&lt;?php
      include("phpgraphlib.php");
      $graph=new PHPGraphLib(1000,1000); 
      include("db_connect.php"); 
      $dataArray=array();
      $graph_array=array();
      $sql="SELECT name,mark1,mark2, entered_time FROM student ";
      $result = mysql_query($sql,$con) ;
      if ($result) {
      while ($row = mysql_fetch_assoc($result)) {
  
      $without_comma_value=explode(',', $row['mark1']);
      $count=count($without_comma_value);
  
      for($i=0;$i&lt;$count;$i++)
      {
      $Val_onebyone= $without_comma_value[$i];
      $num=$i+1;
      $dataArray[$num]=$Val_onebyone; 
       } 
  
      }
      }
  
    $graph-&gt;setBackgroundColor("#F78181");
    $graph-&gt;addData($graph_array);
    $graph-&gt;setBars(false);
    $graph-&gt;setLine(true);
    $graph-&gt;setupYAxis(20, 'black');
    $graph-&gt;setupXAxis(20, 'black');
    $graph-&gt;setTextColor('black');
    $graph-&gt;setDataPoints(true);
    $graph-&gt;setDataPointColor('maroon');
    $graph-&gt;setLineColor('maroon');
    $graph-&gt;createGraph();
     ?&gt;
  </code></pre>
  
  <p>It plots a graph with mark1 values. I want to show mark2 values too. How it is possible ? </p>