diff --git a/htdocs/core/class/dolgraph.class.php b/htdocs/core/class/dolgraph.class.php
index 5cec0232603..8b7bc4acf18 100644
--- a/htdocs/core/class/dolgraph.class.php
+++ b/htdocs/core/class/dolgraph.class.php
@@ -47,8 +47,16 @@ class DolGraph
 	public $data;				// Data of graph: array(array('abs1',valA1,valB1), array('abs2',valA2,valB2), ...)
 	public $title;				// Title of graph
 	public $cssprefix='';		// To add into css styles
+
+	/**
+	 * @var int|string 		Width of graph. It can be a numeric for pixels or a string like '100%'
+	 */
 	public $width=380;
+	/**
+	 * @var int 			Height of graph
+	 */
 	public $height=200;
+
 	public $MaxValue=0;
 	public $MinValue=0;
 	public $SetShading=0;