HTML5 canvas jQuery getContext on classes

Question

This code works:

Answer 1

You'll need to use .each() to iterate over all elements with that class.

$('.myCanvas').each(function() {
   var canvas = $(this)[0];
   var context = canvas.getContext('2d');
  // Do stuff
});

​ Working JSFiddle.

Answer 2

That is because you are using class in jquery.

Change this

var context = $('.dropzone').getContext('2d');

to

var context = $('#dropzone').getContext('2d');

Answer 3

Use .each()

$('.dropzone').each(function(index, element) {
    var context = element.getContext('2d');
    context.beginPath();
    context.moveTo(0, 200);
    context.lineTo(578, 0);
    context.stroke();

    context.beginPath();
    context.moveTo(0, 0);
    context.lineTo(578, 200);
    context.stroke();   
});

Here's an example on jsfiddle.