can we save canvas image in system without right click menu

Hello I have done project in that i can save image like downloading in to div then right click on that it displays save as image,I don't want to do like that. I want download image directly not like the above at the same time i want to save image path in database using SQL server and mvc3 web application.How to save in database I need to use any server side code.
I google it but couldn't find any relevant answer.
Is it possible what i asked if so can any one guide me.
Thanks in advance.
below code is for saving image

function downloadCanvas() {
        var canvas = stage.children[0].canvas;
        var oImgPNG = Canvas2Image.saveAsPNG(canvas, true);
        document.body.appendChild(oImgPNG);
      }

the above code works for me with right click option.
I want to save image directly can any one guide me.When I search in google evry one is using php code.
how to use php code in html5.

Tags: Javascript, HTML5, SQL Server, Database Development (SQL Server), Canvas