Error: Component definition not found: canvas in [LanguageDefinition: xul / html]

I am trying to use canvas in my java project with the zk framework and I get this error when I go open the html I have already imported the canvas library, but even so I have searched but I can not find a solution.

<zk xmlns="http://www.zkoss.org/2005/zul" xmlns:h="http://www.w3.org/1999/xhtml"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:w="http://www.zkoss.org/2005/zk/client"
    xsi:schemaLocation="http://www.zkoss.org/2005/zul
    http://www.zkoss.org/2005/zul/zul.xsd">
<window id="winReservaButacas" title="" border="normal" vflex="1"
    hflex="1" sclass="column1"
    apply="com.controller.ReservaButacas.ReservaButacasController">

                    <canvas id="map" width="800px" height="500px" 
                    style="position:absolute; left:10px; top:10px; z-index:1; 
                    background-color:white" />

</window>