var progressHandler = function (progress){
console.info('Loaded ' + progress.loaded + ' of ' + progress.total);
}

PDFJS.getDocument('pdf.pdf').then(function(pdf){

console.info('Document contains ' + pdf.pdfInfo.numPages + ' pages');

//assign the progress event handler
pdf.loadingTask.onProgress = progressHandler;

// Fetch the page.
pdf.getPage(1).then(function (page) {

// Prepare canvas using PDF page dimensions.
var containerColumn = document.getElementById('pdfContainer');
var canvas = document.getElementById('canvas');
var context = canvas.getContext('2d');
canvas.height = containerColumn.clientHeight;
canvas.width = containerColumn.clientWidth;

var unscaledViewport = page.getViewport(1);
var scale = Math.min((canvas.height / unscaledViewport.height), (canvas.width / unscaledViewport.width));
var viewport = page.getViewport(scale);

// Render PDF page into canvas context.
var renderContext = {
canvasContext: context,
viewport: viewport
};
page.render(renderContext);
});
});