Unable to select sap.ui.core.HTML-content via $()

Hello everyone,

i'm working on a mobile application based on sapui5. Now i need a canvas for drawing graphics (no images).

So i've created a new HTML-Control:

var htmlCanvas = new sap.ui.core.HTML({

    id : "htmlCanvas", // sap.ui.core.ID

    content : "<canvas id=\"myCanvas\" height=\"700\" width=\"700\" style=\"border: solid lightgrey 1px\"></canvas>",

    preferDOM : true, // boolean

    sanitizeContent : false, // boolean

    afterRendering : [ function(oEvent) {} ]

});

and set it within my page.

Unfortunately in my controller i can't access/get it with:

var myCanvas = $("#myCanvas");

console.log(myCanvas);

Could you please help?

Thanks in advance,

Andreas