Save Canvas Image (post The Data String To Php)

I'm looking to learn Javascript and have been wanting to for a while, I got a little tutorial on how to create a HTML5 Canvas drawing application, I'm trying to modify it so I can

Solution 1:

Use form, and send bytes by POST method:

var form = document.createElement("form");
form.setAttribute("action","http://localhost/save_server/");
form.setAttribute("enctype","multipart/form-data");
form.setAttribute("method","POST");
form.setAttribute("target","_self");
form.innerHTML = '<input type="hidden" name="image" value="'+strData+'"/>';
form.submit();