Add extra calrification for html legend (#11614)

diff --git a/docs/samples/legend/html.md b/docs/samples/legend/html.md
index a1400a3d387317d2d67734179e4e5af8a50bf021..3628059428b35830cff3e6aa62760e4b789000a6 100644 (file)
--- a/docs/samples/legend/html.md
+++ b/docs/samples/legend/html.md
@@ -1,6 +1,7 @@
 # HTML Legend
 
-This example shows how to create a custom HTML legend using a plugin and connect it to the chart in lieu of the default on-canvas legend.
+This example shows how to create a custom HTML legend using a plugin and connect it to the chart in lieu of the default on-canvas legend.  
+For an html legend to work you need to place an empty div at your web page with the ID you provide in the options to bind to like so: `<div id="legend-container"></div>`.  
 
 <div id="legend-container"></div>